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381.
Stefan Lüpold George M. Linz Tim R. Birkhead 《Behavioral ecology and sociobiology》2009,63(6):899-909
Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent
evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other
taxa, these relationships are negative, and the causes of these different patterns across taxa are poorly understood. In a
comparative study using New World blackbirds (Icteridae), we tested whether sperm design was influenced by the level of PCSS
and found significant positive associations with the level of PCSS for all sperm components but head length. Additionally,
whereas the absolute length of sperm components increased, their variation declined with the intensity of PCSS, indicating
stabilising selection around an optimal sperm design. Given the diversity of, and strong selection on, sperm design, it seems
likely that sperm phenotype may influence sperm velocity within species. However, in contrast to other recent studies of passerine
birds, but consistent with several other studies, we found no significant link between sperm design and velocity, using four
different species that vary both in sperm design and PCSS. Potential reasons for this discrepancy between studies are discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
382.
Virender K. Sharma George A. K. Anquandah Nasri Nesnas 《Environmental Chemistry Letters》2009,7(2):115-119
The kinetics of the oxidation of endocrine disruptor nonylphenol (NP) by potassium ferrate(VI) (K2FeO4) in water as a function of pH 8.0–10.9 at 25°C is presented. The observed second-order rate constants, k obs, decrease with an increase in pH 269–32 M?1 s?1. The speciation of Fe(VI) (HFeO 4 ? and FeO 4 2? ) and NP (NP–OH and NP–O?) species was used to explain the pH dependence of the k obs values. At a dose of 10 mg L?1 (50 μM) K2FeO4, the half-life for the removal of NP by Fe(VI), under water treatment conditions, is less than 1 min. 相似文献
383.
Melania C. López-Castro Karen A. Bjorndal George D. Kamenov Alan B. Bolten 《Marine Biology》2014,161(10):2269-2278
Many species of marine organisms go through ontogenetic shifts that occur in unknown or inaccessible locations. Finding these areas is crucial to understand connectivity and resilience of populations, both of which have conservation implications. When extrinsic markers are not suitable to track organisms, intrinsic markers can be useful to infer the location of inaccessible areas where these cryptic stages occur. Our study focuses on the location of oceanic foraging areas of the cryptic early juvenile stage of green turtles, Chelonia mydas, in the Atlantic. Due to the small size of hatchlings, the use of telemetry is limited to short periods of time and small spatial ranges, which do not allow determining the location of oceanic foraging areas. We used lead (Pb) stable isotopes to determine the possible location of oceanic foraging areas of small green turtles in the Atlantic Ocean. Pb stable isotope ratios in the scute tissue deposited when turtles were in the oceanic habitat were compared to ratios of major sources of lead in the Atlantic and oceanic areas in the Atlantic to determine the location of oceanic foraging grounds. The Pb isotope ratios in the scute of oceanic-stage green turtles indicated that turtles use different regions in the Atlantic and that they are capable of transatlantic migrations. We compare the oceanic locations identified by this study with those suggested by two previous studies. 相似文献
384.
George Roff Sonia Bejarano Yves-Marie Bozec Maggy Nugues Robert S. Steneck Peter J. Mumby 《Marine Biology》2014,161(6):1385-1393
The 1997/1998 El Niño Southern Oscillation (ENSO) was the most severe coral bleaching event in recent history, resulting in the loss of 16 % of the world’s coral reefs. Mortality was particularly severe in French Polynesia, where unprecedented mortality of massive Porites was observed in lagoonal sites of Rangiroa Atoll. To assess the recovery of massive Porites 15 years later, we resurveyed the size structure and extent of partial mortality of massive Porites at Tivaru (Rangiroa). Surveys revealed an abundance of massive Porites colonies rising from the shallow lagoonal floor. Colony width averaged 2.65 m, reaching a maximum of 7.1 m (estimated age of ~391 ± 107 years old). The relative cover of recently dead skeleton within quadrats declined from 42.8 % in 1998 to zero in 2013, yet the relative cover of old dead skeleton increased only marginally from 22.1 % in 1998 to 26.1 % in 2013. At a colony level, the proportion of Porites dominated by living tissue increased from 34.9 % in 1998 to 73.9 % in 2013, indicating rapid recovery of recent dead skeleton to living tissue rather than transitioning to old dead skeleton. Such rapid post-bleaching recovery is unprecedented in massive Porites and resulted from remarkable self-regeneration termed the ‘Phoenix effect’, whereby remnant cryptic patches of tissue that survived the 1997/1998 ENSO event regenerated and rapidly overgrew adjacent dead skeleton. Contrary to our earlier predictions, not only are large massive Porites relatively resistant to stress, they appear to have a remarkable capacity for recovery even after severe partial mortality. 相似文献
385.
Häring Ivo Fehling-Kaschek Mirjam Miller Natalie Faist Katja Ganter Sebastian Srivastava Kushal Jain Aishvarya Kumar Fischer Georg Fischer Kai Finger Jörg Stolz Alexander Leismann Tobias Hiermaier Stefan Carli Marco Battisti Federica Makri Rodoula Celozzi Giuseppe Belesioti Maria Sfakianakis Evangelos Agrafioti Evita Chalkidou Anastasia Papadakis George Fuggini Clemente Bolletta Fabio Neri Alberto Giunta Guiseppe Scheithauer Hermann Höflinger Fabian Schott Dominik J. Schindelhauer Christian Köhler Sven Linkov Igor 《The Environmentalist》2021,41(2):286-329
Environment Systems and Decisions - Organizational and technical approaches have proven successful in increasing the performance and preventing risks at socio-technical systems at all scales.... 相似文献
386.
David C. Pavlacky Jr. Christian A. Hagen Anne M. Bartuszevige Rich Iovanna Thomas Luke George David E. Naugle 《Conservation biology》2021,35(5):1564-1574
Long-term population declines have elevated recovery of grassland avifauna to among the highest conservation priorities in North America. Because most of the Great Plains is privately owned, recovery of grassland bird populations depends on voluntary conservation with strong partnerships between private landowners and resource professionals. Despite large areas enrolled in voluntary practices through U.S. Department of Agriculture's Lesser Prairie-chicken (Tympanuchus pallidicinctus) Initiative (LPCI), the effectiveness of Farm Bill investments for meeting wildlife conservation goals remains an open question. Our objectives were to evaluate extents to which Conservation Reserve Program (CRP) and LPCI-grazing practices influence population densities of grassland birds; estimate relative contributions of practices to regional bird populations; and evaluate percentages of populations conserved relative to vulnerability of species. We designed a large-scale impact-reference study and used the Integrated Monitoring in Bird Conservation Regions program to evaluate bird population targets of the Playa Lakes Joint Venture. We used point transect distance sampling to estimate density and population size for 35 species of grassland birds on private lands enrolled in native or introduced CRP plantings and LPCI-prescribed grazing. Treatment effects indicated CRP plantings increased densities of three grassland obligates vulnerable to habitat loss, and LPCI grazing increased densities of four species requiring heterogeneity in dense, tall-grass structure (α = 0.1). Population estimates in 2016 indicated the practices conserved breeding habitat for 4.5 million birds (90% CI: 4.0–5.1), and increased population sizes of 16 species , totaling 1.8 million birds (CI: 1.4–2.4). Conservation practices on private land benefited the most vulnerable grassland obligate species (AICc weight = 0.53). By addressing habitat loss and degradation in agricultural landscapes, conservation on private land provides a solution to declining avifauna of North America and scales up to meet population recovery goals for the most imperiled grassland birds. 相似文献
387.
Gritta Veit-Köhler Marleen De Troch Mateja Grego Tania Nara Bezerra Wendy Bonne Guy De Smet Christina Folkers Kai Horst George Chen Guotong Rudy Herman Rony Huys Nikolaos Lampadariou Jürgen Laudien Pedro Martínez Arbizu Armin Rose Michaela Schratzberger Sybille Seifried Paul Somerfield Jan Vanaverbeke Edward Vanden Berghe Magda Vincx Borut Vriser Leen Vandepitte 《Marine Biology》2010,157(8):1819-1835
A large-scale database concerning benthic copepods from the Arctic, Baltic Sea, North Sea, British Isles, Adriatic Sea and Crete was compiled to assess species richness, biodiversity, communities, ecological range size and biogeographical patterns. The Adriatic showed the highest evenness and the most species-rich communities. Assemblages from the North Sea, British Isles, Baltic and Crete had a lower evenness. The British Isles were characterised by impoverished communities. The ecological specificity of copepod species showed two diverging trends: higher specificity of species in more diverse assemblages was observed in the Adriatic, North Sea and Baltic. A uniformly high species specificity disregarding sample diversity was found on Crete and in the British Isles. Benthic copepod communities showed distinct patterns that clearly fit the predefined geographical regions. Communities were distinguishable and β-diversity was found to be high around Europe, indicating a high species turnover on the scale of this investigation. The British Isles and the North Sea were found to be faunistic links to the Baltic and the Arctic. 相似文献
388.
Fluctuating asymmetry (FA) can indicate developmental instability in bilaterally symmetric organisms, and studies have shown
that the degree of asymmetry in male secondary sexual characters influences female mate choice in a number of taxa. In male
Schizocosa ocreata wolf spiders, conspicuous tufts of bristles on the forelegs are a critical component of visual courtship signals, which appear
to play a role in female mate choice. Previous studies have shown that females exhibit reduced receptivity to males with regenerative
asymmetry, a consequence of leg loss and regeneration that causes males to be grossly asymmetric with respect to this important
signaling character. We provide data on the occurrence of FA in the tufts of S. ocreata, and examine further the influence of asymmetry on female mate choice. The distribution of tuft area asymmetry values from
a sample of field-collected males was normal, with a mean value of zero, indicating true FA. For a subset of males measured
directly after field collection and prior to feeding, tuft asymmetry was significantly negatively correlated with measures
of body size (body length) and condition (abdomen volume/cephalothorax width). Receptivity responses of females to visual
signals from live males of similar size varied with the degree of asymmetry in male tufts. Since FA covaries with male body
size and condition, which may also influence behavioral vigor, we used video image manipulation to alter the degree of asymmetry
in tufts of a courting male while holding size and condition constant. Asymmetry treatments represented values within the
range of natural FA variation as well as more extreme values characteristic of regenerative asymmetry. With the confounding
effects of male size, condition, and behavior held constant, female spiders exhibited reduced receptivity responses to all
experimental asymmetric video images relative to a control video stimulus. There were no differences in the frequency of female
receptivity among the various asymmetry treatments, suggesting that discrimination against asymmetry in conspecific male signal
characters is not simply a rejection of extreme phenotypes. Results suggest that asymmetry in a key male secondary character
used in visual signaling, independent of any concomitant behavioral or size factor, is an important criterion in mate choice.
Received: 26 February 1998 / Accepted after revision: 12 September 1998 相似文献
389.
James Otto Deputy Director Koh Naito Mining Expert George Pring Professor 《Natural resources forum》1999,23(4):323-334
This paper offers a new perspective on the environmental laws in Asian nations affecting the exploration, mining, and reclamation activities of the mineral resource industry: the perspective of the senior government officials in those countries, whose job is to enforce these new environmental laws. The article presents the results of a 1998 survey of national environmental officials in Asia conducted by the Colorado School of Mines and the Metal Mining Agency of Japan. Officials in 10 diverse countries—Cambodia, China, Indonesia, Lao PDR, Malaysia, Myanmar, Mongolia, Philippines, Thailand and Vietnam—responded to a detailed questionnaire covering applicable laws, agencies, protected areas, covered mineral activities, financial assurance, environmental impact assessment, public involvement, environmental standards, permit and reclamation requirements.
The survey confirms that Asian nations are part of the global trend towards national government regulatory structures that balance mineral development objectives with environmental considerations. The survey also shows developing regulatory systems (some embryonic, some more mature) utilizing a combination of mining and environmental acts, and often an 'insider' perspective of the national officials administering the laws. While that perspective is not without its biases (not least the rigor of enforcement), it may nevertheless be of use in company planning. The emerging regulatory picture contradicts the conventional notion that it is the 'lower' level of regulation in Asia that is attracting foreign direct investment in mining. 相似文献
The survey confirms that Asian nations are part of the global trend towards national government regulatory structures that balance mineral development objectives with environmental considerations. The survey also shows developing regulatory systems (some embryonic, some more mature) utilizing a combination of mining and environmental acts, and often an 'insider' perspective of the national officials administering the laws. While that perspective is not without its biases (not least the rigor of enforcement), it may nevertheless be of use in company planning. The emerging regulatory picture contradicts the conventional notion that it is the 'lower' level of regulation in Asia that is attracting foreign direct investment in mining. 相似文献
390.
The N simulation model, DRAINMOD-N II, was field-tested using a 6-yr data set from an artificially drained agricultural site located in eastern North Carolina. The test site is on a nearly flat sandy loam soil which is very poorly drained under natural conditions. Four experimental plots, planted to a corn (Zea mays)-wheat (Triticum aestivum L.)-soybean (Glycine max.) rotation and managed using conventional and controlled drainage, were used in model testing. Water table depth, subsurface drainage, and N concentration in drain flow were measured and meteorological data were recorded continuously. DRAINMOD-N II was calibrated using the data from one plot; data sets from the other three plots were used for model validation. Simulation results showed an excellent agreement between observed and predicted nitrate-nitrogen (NO(3)-N) losses in drainage water over the 6-yr period and a reasonable agreement on an annual basis. The agreement on a monthly basis was not as good. The Nash-Sutcliffe modeling efficiency (EF) for monthly predictions was 0.48 for the calibration plot and 0.19, 0.01, and -0.02 for the validation plots. The value of the EF for yearly predictions was 0.92 for the calibration plot and 0.73, 0.62, and -0.10 for the validation plots. Errors in predicting cumulative NO(3)-N losses over the 6-yr period were remarkably small; -1.3% for the calibration plot, -8.1%, -2.8%, and 4.0% for the validation plots. Results of this study showed the potential of DRAINMOD-N II for predicting N losses from drained agricultural lands. Further research is needed to test the model for different management practices and soil and climatological conditions. 相似文献