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151.
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153.
Albert Rango Victor van Katwijk 《Journal of the American Water Resources Association》1990,26(1):135-144
ABSTRACT: The snowmelt-runoff model (SRM) was used to produce accurate simulations of streamfiow during the snowmelt period (April-September) for ten years on the Rio Grande Basin (3419 km2) near Del Norte, Colorado, U.S.A. In order to use SRM in the forecast situation, it was necessary to develop a family of snow cover depletion curves for each elevation zone based on accumulated snow water equivalent on April 1. Selection of an appropriate curve for a particular year from snow course measurements allows input of the daily snow cover extent to SRM for forecast purposes. Data from three years (1980, 1981, and 1985) were used as a quasi-forecast test of the procedure. In these years forecasted snow cover extent data were input to SRM, but observed temperature and precipitation data were used. The resulting six-month hydrographs were very similar to the hydrographs in the ten simulation years previously tested based on comparisons of performance evaluation criteria. Based on this result, the Soil Conservation Service (SCS) requested SRM forecasts for 1987 on the Rio Grande. Using the same procedure but with SCS estimated temperature and precipi-tation data, SRM produced a forecast hydrograph that had a r2= 0.82 and difference in seasonal volume of 4.4 percent. To approximate actual operational conditions, SRM computed daily flows were updated every seven days with measured flows. The resulting forecast hydrograph had a R2= 0.90 and a difference in volume of 3.5 percent. The method developed needs to be refined and tested on additional years and basins, but the approach appears to be applicable to operational runoff forecasting using remote sensing data. 相似文献
154.
Antonio Cao Angela M. Falchi Teresa Tuveri Maria T. Scalas Giovanni Monni Cristina Rosatelli 《黑龙江环境通报》1986,6(3):159-167
In this report we have summarized our experience with the prenatal diagnosis of β-thalassemia in 1000 pregnancies followed at least until 12 months after birth. In the majority of these cases, the thalassemia lesion was the nonsense mutation at the codon corresponding to amino acid 39, which produces the hematological phenotype of β-thalassemia. Fetal blood sampling was carried out by placental aspiration, by which a sufficient amount of fetal blood for analysis was obtained in the majority of cases (99 per cent). The fetal mortality associated with fetal blood sampling was 6·3 per cent. Those placental samples contaminated by maternal cells were successfully purified by Ørskov lysis. Fetal blood was analysed by globin chain synthesis on CM–52 columns, which gave reliable results. Two misdiagnoses (0·2 per cent) have been made of which one was due to a non-globin protein co-migrating with the β-chains while the other resulted from a misclassification of the type of thalassemia segregating in the family. 相似文献
155.
Dr Helen M. Kingston Consultant Clinical Geneticist Umberto Nicolini John Haslam Tony Andrews 《黑龙江环境通报》1993,13(7):637-642
46,XY/47,XY, + 17p + mosaicism was found in two primary amniotic fluid cultures (AFCs). Fetal blood karyotype was normal, but ultrasonography revealed Dandy-Walker malformation and bilateral choroid plexus cysts. Following termination of pregnancy, fetal examination revealed post-axial polydactyly and neuroblastoma-in-situ affecting both adrenals in addition to the cerebellar abnormalities. Mosaicism for the aberrant cell line was confirmed in all fetal tissues sampled and in the placenta. 相似文献
156.
A case of true fetal mosaicism 46,XY/47,XY, + 17 was diagnosed in amniotic fluid cells. After genetic counselling and unsuccessful periumbilical blood sampling the pregnancy continued to term, and a healthy male infant was born. Lymphocytes of the newborn had a normal karyotype. Follow-up of the child at age 18 months showed normal physical and mental development indicating that the trisomic cell line was restricted most probably to the extra fetal tissue. 相似文献
157.
Dr. H. Grosse-Wilde E. Valentine-Thon U. Vögeler E. Passarge F. Lorenzen W. G. Sippell F. Bidlingmaier D. Knorr 《黑龙江环境通报》1988,8(2):131-143
In 18 families at risk for the HLA-linked, 21-hydroxylase deficient form of autosomal recessive congenital adrenal hyperplasia (CAH), prenatal diagnosis (PD) was performed using two methods: (1) HLA-A,B,C typing and in the latter 11 cases also DR typing of cultured amniotic fluid cells (AFC) using the standard microcytotoxicity assay, and (2) measurement of second trimester amniotic fluid 17-hydroxyprogesterone (17-OHP) concentration using gel chromatography and radioimmunoassay. The accuracy of the prenatal predictions was confirmed by postnatal HLA typing of umbilical cord blood lymphocytes and by clinical evaluation. In 16/18 families, both HLA typing of AFC and 17-OHP measurements proved informative for PD. The predictions of both methods were concordant in 14/16 families (88 per cent). In ten of these families, a normal fetus was predicted, and in four, an affected fetus; all pregnancies were carried to term and all predictions were confirmed postnatally. In 2/16 cases (12 per cent), however, the predictions were discordant: the prenatal HLA typing indicated an affected fetus, whereas the 17-OHP values predicted a normal fetus. Both pregnancies were continued and two healthy boys were delivered. The discordance proved to be due to a ‘missed’ HLA antigen in one case and to serologically cross-reactive HLA antigens in the second. Finally, in 2/18 cases, prenatal assessment of fetal genotype had to rely on HLA typing alone as 17-OHP measurement was not performed in one family and in the second family the 17-OHP values obtained were not informative due to inadvertent continuation of hormone therapy to the date of amniocentesis. In both cases, the HLA typing data accurately predicted a normal fetus. In conclusion, a combination of HLA typing of cultured AFC and 17-OHP measurements of amniotic fluid permits accurate prenatal diagnosis of CAH in most cases (88 per cent). In addition, the supplementary use of HLA-DR typing of AFC as presented here for the first time proved helpful in families with HLA-A.B homozygosity due to parental sharing of antigens and can be informative for identifying HLA-B/21-OH recombinant haplotypes. 相似文献
158.
不同氮浓度下三角褐指藻生长特性和化学组成 总被引:2,自引:0,他引:2
三角褐指藻是一类海洋单细胞硅藻,富含多不饱和脂肪酸,可以作为鱼、虾、贝等理想的饵料。而近年该藻曾多次在我国沿海海域发生暴发性增殖,给当地生态环境带来了一定的影响。为了探讨不同氮浓度对三角褐指藻生长特性和化学组成的影响,设置了低氮(44 μ mol.L-1)、中氮(880 μmol.L-1)和高氮(4 400 μmol.L-1)浓度三种处理,着重测定三角褐指藻的细胞密度、比生长率、生物量、可溶性糖、蛋白质含量和叶绿素含量等指标。结果表明,高氮浓度明显地促进了藻细胞的生长繁殖。高氮浓度下的藻细胞密度、比生长率和生物量分别比低氮浓度下的提高了 5.38 倍、0.81 倍和 2.86 倍。藻生长前期,高氮浓度和中氮浓度下的生长曲线相似,呈现一个"S"型的曲线。另外,高氮浓度下的藻细胞可溶性糖、蛋白质和叶绿素a含量分别是低氮浓度下的 2.5 倍、1.5 倍和 15 倍,说明高氮浓度促进了藻细胞化学组成的转化和积累。结果揭示,氮浓度可能是导致三角褐指藻近年在我国沿海海域发生暴发性增殖的重要因素。 相似文献
159.
在c(NaCl)=200mmol/L,t=14d胁迫条件下,盐敏感品种糖高粱(T)成熟叶生长抑制、含水量的下降和质膜透性均明显大于耐盐品种独角虎(D);盐胁迫下,质外体和共质体中Na+浓度明显增加,增加的幅度是质外体大于共质体,T大于D.相反,盐胁迫下质外体和共质体Ca2+浓度均明显下降,研究结果表明:质外体Na+浓度剧增并没有改变细胞膨压,而可能通过取代质膜上Ca2+而破坏质膜选择透性,从而引发盐害 相似文献
160.