全文获取类型
收费全文 | 22102篇 |
免费 | 44篇 |
国内免费 | 76篇 |
专业分类
系统科学 | 84篇 |
丛书文集 | 279篇 |
教育与普及 | 68篇 |
理论与方法论 | 92篇 |
现状及发展 | 9981篇 |
研究方法 | 964篇 |
综合类 | 10423篇 |
自然研究 | 331篇 |
出版年
2013年 | 179篇 |
2012年 | 332篇 |
2011年 | 649篇 |
2010年 | 144篇 |
2008年 | 367篇 |
2007年 | 428篇 |
2006年 | 397篇 |
2005年 | 426篇 |
2004年 | 390篇 |
2003年 | 382篇 |
2002年 | 380篇 |
2001年 | 603篇 |
2000年 | 606篇 |
1999年 | 416篇 |
1992年 | 389篇 |
1991年 | 311篇 |
1990年 | 347篇 |
1989年 | 337篇 |
1988年 | 344篇 |
1987年 | 340篇 |
1986年 | 318篇 |
1985年 | 443篇 |
1984年 | 302篇 |
1983年 | 274篇 |
1982年 | 255篇 |
1981年 | 247篇 |
1980年 | 314篇 |
1979年 | 720篇 |
1978年 | 562篇 |
1977年 | 576篇 |
1976年 | 445篇 |
1975年 | 491篇 |
1974年 | 632篇 |
1973年 | 564篇 |
1972年 | 622篇 |
1971年 | 643篇 |
1970年 | 831篇 |
1969年 | 705篇 |
1968年 | 731篇 |
1967年 | 663篇 |
1966年 | 605篇 |
1965年 | 408篇 |
1964年 | 123篇 |
1959年 | 217篇 |
1958年 | 390篇 |
1957年 | 299篇 |
1956年 | 271篇 |
1955年 | 222篇 |
1954年 | 203篇 |
1948年 | 177篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
931.
D Gerlier F Sakai J F Doré 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,286(5):439-442
The Gross virus associated cell surface antigen GCSAa was extracted from (C58NT)D cells by solubilization of membranes with detergent and partially purified. This antigen was entraped in liposomes. Absorption experiments of the cytotoxic activity towards EmaleG2 cells of a W/Fu anti (C58NT)D serum showed the presence of the antigen at the surface of sensibilized liposomes. 相似文献
932.
Summary The formation of the myotomes to chick embryos was studied by using experimental and scanning electron microscope techniques. With the aid of the quail-chick marker system, it was demonstrated that the dermatome gives rise to the myotome plate. SEM studies support the conclusion that the myotome cells originate only from the edges of the dermatome.Supported by the Deutsche Forschungsgemeinschaft (Ch 44/2). 相似文献
933.
K. Silberbauer H. Sinzinger Maya Winter W. Feigl F. Ring 《Cellular and molecular life sciences : CMLS》1978,34(11):1471-1472
Summary Morphological control of Moncada's bioassay for prostacyclin (PG I2) activity measurement shows that the activity depends not only on endothelium, but in important amounts on subendothelial tissue too. Therefore, it can be concluded that platelet thrombus formation after endothelial cell injury does not depend only on the PG I2-producing ability of the tissue. 相似文献
934.
Summary T-2 toxin, a trichothecene metabolite of several Fusarium spp. causes depigmentation of dark mouse hair at the site of its application. Calcium pantothenate, though usually considered as antigreying factor, caused depigmentation at the site of its i.p. injections, at high concentration. 相似文献
935.
Directed outgrowth of optic fibres regenerating in vitro 总被引:1,自引:0,他引:1
936.
937.
Summary I.v. botulinum toxin after 60–90 min abolished the dose-response relationship between pentagastrin and gastric acid secretion in anesthetized rats and guinea-pigs. The toxin reduced but did not abolish the acid stimulatory effect of histamine. As expected, the acid response to vagal stimulation was abolished and that to methacholine in rats was unaltered by the toxin.Acknowledgment. We are grateful to the generosity of Dr Edward J. Schantz, Food Research Institute, University of Wisconsin, for the botulinum toxin used. — This research was supported by NIH grant 1 RO1 AM 17125, The Secretion of Pepsin. 相似文献
938.
The human B cell-specific alloantigen which is closely linked genetically to HLA contains two non-covalently associated, sialogycoprotein subunits of molecular weight (MW) 29,000 (p29), and 34,000 (p34). Although p29 and p34 have different amino-terminal sequences, their tyrosine peptide maps indicate considerable similarity in other portions of their polypeptide chains. Thus the genes for their proteins may have evolved by duplication of a common ancestral gene. Another lymphocyte cell surface protein of MW 16,000 (p16) has also been characterised. Both p16 and p44 (the heavy chain of HLA-A,B antigens) have been compared with p29 and p34. 相似文献
939.
940.