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101.

Objective

Children and adults with talipes equinovarus (TEV) have smaller calves and shorter feet compared to non-affected controls. Do these changes have a prenatal onset?

Methods

A prospective cohort study (January 2020–July 2021) was conducted with serial ultrasonographic measurements at 20 and 28 weeks gestation and measurements directly and 6 weeks after birth. Calf circumference and width, foot length and length of humerus, ulna, radius, femur, tibia and fibula were measured in TEV and were compared to a control population. Calculated sample size necessitated a minimal population of 10 cases with TEV and 50 controls.

Results

Twenty cases with TEV and 62 controls were included. Fetal calf circumference (p < 0.001) and width (p < 0.001) were smaller in the TEV group in comparison to the control group, which persisted after birth. Growth in foot length (p < 0.001) and calf width (p 0.003) declined prenatally over time. The bone lengths and upper leg circumference were not smaller or shorter in TEV compared to controls.

Conclusion

This prospective cohort study demonstrated the prenatal onset of reduced calf and foot size in fetuses with TEV from 20 weeks and onwards, which persists directly after birth. To investigate whether reduction in circumference initiates TEV or is caused by TEV, further examination is needed.  相似文献   
102.

Objective

Outcome data from cell-free DNA (cfDNA) screening in twin gestations are limited. This study adds an appreciable number of confirmed outcomes to the literature, and assesses performance of cfDNA screening in twins over a 4.5-year period at one large clinical laboratory.

Method

Prenatal cytogenetic and SNP microarray results were cross-referenced with cfDNA results for twin pregnancies, yielding 422 matched cases. Using diagnostic results as truth, performance of cfDNA screening in this population was assessed.

Results

Of the 422 twin pregnancies with both cfDNA and diagnostic results, 3 specimens failed amniocyte analysis, and 48 samples (11.5%) were nonreportable from the initial cfDNA draw. Analysis of the 371 reportable samples demonstrated a collective sensitivity of 98.7% and specificity of 93.2% for trisomies 21/18/13. Positive predictive values (PPVs) in this study population, which is enriched for aneuploidy, were 78.7%, 84.6%, and 66.7% for trisomy 21, 18, and 13, respectively.

Conclusion

CfDNA screening in a cohort of twin pregnancies with matched diagnostic results showed superior performance compared to traditional serum biochemical screening in twins. This study adds to a growing body of evidence suggesting that cfDNA is an accurate and reliable screening tool for the major trisomies in twin pregnancies.
  相似文献   
103.
Using an estimated background nitrogen (N) deposition value of 0.5 kg N x ha(-1) x yr(-1) in 1900, and a 19-year record of measured values from Loch Vale (Colorado, USA; NADP site CO98), I reconstructed an N-deposition history using exponential equations that correlated well with EPA-reported NO(x) emissions from Colorado and from the sum of emissions of 11 western states. The mean wet N-deposition values for the period 1950-1964 was approximately 1.5 kg N x ha(-1) x yr(-1), corresponding to the reported time of alteration of diatom assemblages attributed to N deposition in alpine lakes in Rocky Mountain National Park (USA). This value becomes the critical load defining the threshold for ecological change from eutrophication. Thus if an N-deposition threshold for ecological change can be identified, and the date at which that threshold was crossed is known, hindcasting can derive the amount of atmospheric deposition at the time of change, at least for alpine lakes. Independent support for the technique and the deposition amount comes from experimental studies, ecosystem modeling, and paleolimnological records from northern Wyoming (USA).  相似文献   
104.
The detrimental effects of a ringing phone on cognitive performance were investigated in four experiments. In Experiments 1 and 2, the effects of different types of sounds (a standard cell phone ring, irrelevant tones and an instrumental song commonly encountered by participants) on performance were examined. In Experiment 1, slower responses were observed in all auditory groups relative to a silence condition, but participants in the ring and song conditions recovered more slowly. In Experiment 2, participants who were warned about the potential for distraction recovered more quickly, suggesting a benefit of this prior knowledge. This investigation continued in a college classroom setting (Experiments 3a and 3b); students were exposed to a ringing cell phone during the lecture. Performance on a surprise quiz revealed low accuracy rates on material presented while the phone was ringing. These findings offer insight into top-down cognitive processes that moderate involuntary orienting responses associated with a common stimulus encountered in the environment.  相似文献   
105.
ABSTRACT

The medical community has long recognized that humans exhale volatile organic compounds (VOCs). Several studies have quantified emissions of VOCs from human breath, with values ranging widely due to variation between and within individuals. The authors have measured human breath concentrations of isoprene and pentane. The major VOCs in the breath of healthy individuals are isoprene (12580 ppb), acetone (1.2-1,880 ppb), ethanol (13-1,000 ppb), methanol (160-2,000 ppb) and other alcohols. In this study, we give a brief summary of VOC measurements in human breath and discuss their implications for indoor concentrations of these compounds, their contributions to regional and global emissions budgets, and potential ambient air sampling artifacts. Though human breath emissions are a negligible source of VOCs on regional and global scales (less than 4% and 0.3%, respectively), simple box model calculations indicate that they may become an important (and sometimes major) indoor source of VOCs under crowded conditions. Human breath emissions are generally not taken into account in indoor air studies, and results from this study suggest that they should be.  相似文献   
106.
The debate on scale use in river management focuses primarily on the (lack of) fit between the bio-geophysical and institutional systems. However, in this article we focus on the ‘subjective’ aspect of scale preferences in water governance. We apply an adapted version of the Integrated Scale Hierarchy for Rivers to determine the degree of fit between the scale preferences of the actors involved in a Dutch case study and the scale requirements of the innovative river management concept. This allows us to understand which riverine processes and characteristics are regarded as important by the different actors and to identify mismatches in scale perspectives as they manifest themselves in water management practice. We discover that inflexibility in scale use on the part of the involved actors places bounds on the design and quality of interventions and demonstrate that a more flexible use of scales in the design phase of a river management intervention has the potential to lead to more effective solutions.  相似文献   
107.
Contribution from Fourth World Wilderness Congress-Acid Rain Symposium, Denver (Estes Park), Colorado, September 11–18, 1987.  相似文献   
108.
Bessler  W. G.  Baron  D. 《Die Naturwissenschaften》1988,75(10):496-502
The following article describes both theoretical basis and detailed method for producing monoclonal antibodies in the systems of mouse and man. It further outlines methods to characterize monoclonal antibodies and produce them on a larger scale. Finally, reference is made to their application in research and medicine, and further developments are indicated.  相似文献   
109.
110.
This study proposed and tested relationships pertaining to employee perceptions of psychological contract type over time. Using a longitudinal design, we examined the mediated role that adequacy of social accounts and psychological contract fulfillment play in determining the development of contract perceptions. More specifically, our model posits that perceptions of contract type will influence employee perceptions of the adequacy of social accounts that are offered by the organization and its agents to explain job‐related decisions. These initial perceptions of social accounts at Time 1 were expected to impact perceptions of psychological contract fulfillment at Time 2 (6 months later) and psychological contract fulfillment was proposed to be positively associated with perceptions of a relational psychological contract. Results support the mediating roles of social accounts and psychological contract fulfillment in determining perceptions of contract type over time. Practical implications of these findings and directions for future research are discussed. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
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