全文获取类型
收费全文 | 29557篇 |
免费 | 334篇 |
国内免费 | 253篇 |
专业分类
安全科学 | 856篇 |
废物处理 | 1121篇 |
环保管理 | 4125篇 |
综合类 | 5160篇 |
基础理论 | 7766篇 |
环境理论 | 14篇 |
污染及防治 | 7440篇 |
评价与监测 | 1809篇 |
社会与环境 | 1644篇 |
灾害及防治 | 209篇 |
出版年
2022年 | 218篇 |
2021年 | 231篇 |
2020年 | 201篇 |
2019年 | 258篇 |
2018年 | 396篇 |
2017年 | 420篇 |
2016年 | 618篇 |
2015年 | 483篇 |
2014年 | 673篇 |
2013年 | 2388篇 |
2012年 | 830篇 |
2011年 | 1161篇 |
2010年 | 953篇 |
2009年 | 1010篇 |
2008年 | 1196篇 |
2007年 | 1246篇 |
2006年 | 1158篇 |
2005年 | 917篇 |
2004年 | 976篇 |
2003年 | 916篇 |
2002年 | 847篇 |
2001年 | 1127篇 |
2000年 | 802篇 |
1999年 | 477篇 |
1998年 | 403篇 |
1997年 | 368篇 |
1996年 | 401篇 |
1995年 | 427篇 |
1994年 | 438篇 |
1993年 | 390篇 |
1992年 | 414篇 |
1991年 | 387篇 |
1990年 | 413篇 |
1989年 | 380篇 |
1988年 | 318篇 |
1987年 | 279篇 |
1986年 | 290篇 |
1985年 | 299篇 |
1984年 | 320篇 |
1983年 | 313篇 |
1982年 | 312篇 |
1981年 | 315篇 |
1980年 | 268篇 |
1979年 | 270篇 |
1978年 | 215篇 |
1977年 | 210篇 |
1975年 | 182篇 |
1974年 | 210篇 |
1973年 | 188篇 |
1972年 | 221篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
281.
Research in molecular neurobiology has recently entered a new phase of rapid development as a result of the application of the techniques of molecular genetics. This is illustrated by recent work on the electric ray (Torpedo marmorata and T. californica), whose electric organ is a rich source of cholinergic synapses. Other examples from recent literature of the application of the recombinant DNA technique to the mammalian central nervous system are given and possible future developments are discussed. 相似文献
282.
K. E. Kaissling G. Kasang H. J. Bestmann W. Stransky O. Vostrowsky 《Die Naturwissenschaften》1978,65(7):382-384
The female silkmoth Bombyx mori L. emits a second pheromone component bombykal (E-10, Z-12-hexade-cadien-1-al) in addition to the well-known sexual attractant bombykol (E-10, Z-12-hexadecadien-1-ol). Bombykal stimulates its own specialized and highly sensitive olfactory cells of the male moth. Surprisingly, the aldehyde inhibits the release of the male's wing-fluttering response to bombykol. 相似文献
283.
284.
285.
Mary C. Phelan Ph.D. Robert A. Saul Thompson A. Gailey Jr Steven A. Skinner 《黑龙江环境通报》1995,15(3):274-277
Mosaicism for the Wolf-Hirschhorn syndrome, del(4)(p16), is extremely rare and has not been reported in association with a numerical chromosome abnormality. We report the prenatal diagnosis of mosaic del(4)(p16) and non-mosaic trisomy 21 in a 16-week female fetus. The pregnancy ended in spontaneous abortion at 34 weeks secondary to fetal demise. The fetus had features of both 4p – and trisomy 21. 相似文献
286.
M. Peter Marinkovich MD Guerrino Meneguzzi Robert E. Burgeson Claudine Blanchet-Bardon Karen A. Holbrook Lynne T. Smith Angela M. Christiano Jean-Paul Ortonne 《黑龙江环境通报》1995,15(11):1027-1034
Herlitz junctional epidermolysis bullosa (HJEB) is a severe blistering disorder which usually results in death during infancy. We have previously shown that the anchoring filament protein laminin-5 (kalinin/nicein), which mediates keratinocyte attachment and dermal–epidermal cohesion, is abnormally expressed in individuals with HJEB. Laminin-5 was detected by Western blot analysis in amniotic fluid from 44 consecutive normal secondtrimester control pregnancies, but was undetectable in second-trimester amniotic fluid from four pregnancies with fetuses affected by HJEB. In one case of severe non-Herlitz JEB, laminin-5 was detected in both amniotic fluid and skin. In human amniotic fluid, the laminin-5 a3 subunit was processed to a major 165 kD species and a minor 145 kD species and the β2 subunit was partially processed to 105 kD. Although laminin-5 was covalently associated with laminin-6 (K-laminin) in amniotic membrane, no covalent interaction was detected in amniotic fluid. Laminin-5 from amniotic fluid strongly supported keratinocyte attachment. These results suggest that Western blot analysis of second-trimester amniotic fluid is useful in determining the prenatal diagnosis of HJEB and that laminin-5 may serve a physiologically important function in amniotic fluid. 相似文献
287.
Ariel Weissman Reuwen Achiron M.D. Jacob Kuint Shlomo Lipitz Shlomo Mashiach Itamar Avigad 《黑龙江环境通报》1994,14(9):888-891
A case of gastric outlet obstruction diagnosed prenatally at 22 weeks' gestation is described. The differential diagnosis and the clinical management of this rare condition are discussed, and an updated literature review is presented. 相似文献
288.
Catherine Donner M.D. Corinne Liesnard Françoise Brancart Frederic Rodesch 《黑龙江环境通报》1994,14(11):1055-1059
Cytomegalovirus (CMV) is the most common cause of intrauterine infection. Recent publications show amniocentesis to have an 81–100 per cent sensitivity in antenatal diagnosis after 21 weeks' gestation. Testing before 21 weeks' gestation is less well documented. We performed 36 amniocenteses between 14 and 20 weeks' gestation. The sensitivity was 45 per cent and the specificity 100 per cent. Implications and possible causes of this low sensitivity are discussed. 相似文献
289.
Five cases of mosaicism for an isochromosome of 20q have been detected from a total of 50 000 cases analysed for prenatal diagnosis by amniocentesis. Karyotypes were designated mos 46,X_/46,X_,i(20q). In all cases, the abnormal cell line was detected in more than one primary culture, thus fulfilling the criterion for true (level III) mosaicism. Indications for prenatal diagnosis were parental anxiety (two cases), low maternal serum alpha-fetoprotein (AFP) (two cases), and high maternal serum AFP (one case). Level II ultrasounds on all five fetuses were normal, and the abnormal cell line was never detected in fetal blood and/or cord blood. All five pregnancies were continued and had normal outcomes, with birth weights ranging from 2.4 to 3.8 kg. The development of all five children has been normal, with the oldest child in the study now 4 years of age. We suggest that the abnormal cell line in each case was of extrafetal origin, and that this may be one of the more common examples of this phenomenon, occurring in approximately 1/10000 prenatal diagnoses. Mosaicism i(20q) may have been missed in the past because of the higher resolution necessary to detect this subtle change. 相似文献
290.
Dr. Michael J. McCormack Margaret E. Rylance William E. Mackenzie John Newton 《黑龙江环境通报》1990,10(4):253-255
The attitudes of 190 patients who had undergone chorionic villus sampling (CVS) were assessed by means of a questionnaire. One hundred and fifty-two patients replied of whom 68 (45 per cent) were referred because of increased maternal age and in the other 84 cases the indications included previous chromosomal abnormalities, fetal sexing, DNA analysis, and biochemical analysis. One hundred and twenty-two patients had a transcervical procedure, 24 had a transabdominal, and six patients required both procedures. One hundred and forty-one patients (93 per cent) reported CVS to be a satisfactory procedure, and the same percentage thought earlier diagnosis was beneficial. Thirty-nine patients (81 per cent) reported a better experience with CVS than with a previous amniocentesis. A majority of patients (93 per cent) wished a CVS in a future pregnancy and 137 patients (97 per cent) would accept a risk of miscarriage from the procedure of twice that quoted for amniocentesis (1 per cent). 相似文献