全文获取类型
收费全文 | 11175篇 |
免费 | 1020篇 |
国内免费 | 11篇 |
专业分类
12206篇 |
出版年
2022年 | 75篇 |
2021年 | 173篇 |
2020年 | 94篇 |
2019年 | 148篇 |
2018年 | 143篇 |
2017年 | 130篇 |
2016年 | 244篇 |
2015年 | 364篇 |
2014年 | 434篇 |
2013年 | 565篇 |
2012年 | 728篇 |
2011年 | 640篇 |
2010年 | 435篇 |
2009年 | 356篇 |
2008年 | 549篇 |
2007年 | 548篇 |
2006年 | 519篇 |
2005年 | 504篇 |
2004年 | 491篇 |
2003年 | 429篇 |
2002年 | 440篇 |
2001年 | 126篇 |
2000年 | 103篇 |
1999年 | 146篇 |
1998年 | 143篇 |
1997年 | 91篇 |
1996年 | 106篇 |
1995年 | 86篇 |
1994年 | 106篇 |
1993年 | 83篇 |
1992年 | 107篇 |
1991年 | 118篇 |
1990年 | 104篇 |
1989年 | 89篇 |
1988年 | 78篇 |
1987年 | 91篇 |
1986年 | 84篇 |
1985年 | 65篇 |
1984年 | 105篇 |
1983年 | 81篇 |
1982年 | 98篇 |
1981年 | 80篇 |
1980年 | 108篇 |
1979年 | 73篇 |
1978年 | 88篇 |
1977年 | 85篇 |
1976年 | 74篇 |
1975年 | 67篇 |
1974年 | 69篇 |
1973年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
T Henry A Ferguson 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,85(2):491-496
Informative crosses have verified the genetic basis of a polymorphism at the Ldh-1 locus in brown trout and enzyme activity measurements indicate that the previously described polymorphism at this locus is best explained by a null allele. The LDH-1, LDH-2, LDH-3 and LDH-4 homotetrameric isozymes were purified and subjected to enzyme kinetic analysis. While LDH-1 and LDH-2 displayed catalytic equivalence, important kinetic differences were found between the LDH-3 and LDH-4 isozymes. 相似文献
12.
13.
Didier Arseguel Armand Lattes Michel Baboul ne 《Biocatalysis and Biotransformation》1990,3(3):217-225
Horseradish peroxidase was chemically conjugated on its carbohydrate moieties with short aliphatic chains (C8 and C16). An analytical method using FT.IR spectroscopy was developed to analyze this alteration in enzyme structure. This method is non-destructive, and can be applied directly to samples of the reaction mixture. More general applications of this technique are described and discussed. 相似文献
14.
15.
Didier Rognan 《Journal of Physiology》2006,99(2-3):232-244
The concomitant development of in silico screening technologies and of three-dimensional information on therapeutically relevant macromolecular targets makes it possible to navigate in the structural proteome and to identify targets fulfilling user-defined queries. This review illustrates some in-house recent advances in the development of target libraries and how they can be browsed to unravel chemogenomic information. 相似文献
16.
17.
Madhusoodana P. Nambiar Tatsuya Oda Chaohua Chen Yasuo Kuwazuru Henry C. Wu 《Journal of cellular physiology》1993,154(2):222-228
The intracellular pathway following receptor-mediated endocytosis of cholera toxin was studied using brefeldin A (BFA), which inhibited protein secretion and induced dramatic morphological changes in the Golgi region. In both mouse Y1 adrenal cells and CHO cells, BFA at 1 μg/ml caused a 80–90% inhibition of the cholera toxin (CT)-elevation of intracellular cAMP. The inhibition of the cytotoxicity of CT by BFA was also observed in a rounding assay of Y1 adrenal cells. The inhibition of CT cytotoxicity by BFA was dose dependent, with the ID50 value similar to the LD50 of BFA in Y1 adrenal cells. Binding and internalization of [125I]-cholera toxin in Y1 adrenal cells was not affected by BFA. Unlike the BFA-sensitive cell lines such as Y1 adrenal and CHO cells, BFA at 1 μg/ml did not inhibit the cytotoxicity of CT in PtK1 cells, of which the Golgi structure was BFA-resistant. These results strongly suggest that a BFA-sensitive Golgi is required for the protection of CT cytotoxicity by BFA. In contrast, elevation of the intracellular cAMP by forskolin, which acts directly on the plasma membrane adenylate cyclase, was not affected by BFA. These observations indicate that the intoxication of target cells by CT requires an intact Golgi region for its intracellular trafficking and/or processing. In this respect, CT shares a common intracellular pathway with ricin, Pseudomonas toxin, and modeccin, even though their structures and modes of action are very different. © 1993 Wiley-Liss, Inc. 相似文献
18.
Henry R. Mainwaring 《Archives of microbiology》1971,75(4):296-303
Summary The cytology of Podospora arizonensis, an apomictic pyrenomycete, has been studied from crozier formation to the first mitotic division in the ascus, using phase contrast light microscopy. Increase in ascus size is accompanied by morphological changes in the chromosomes which are reminiscent of the changes associated with meiosis in normal ascomycetes. The nucleolus is seen to increase in size during the phase of maximal ascus growth, and to decrease thereafter. The significance of these events is discussed. 相似文献
19.
Making use of a newly designed mobilizable suicide vector, the genetic determinants encoding Shigella sonnei lipopolysaccharide (LPS) were stably integrated into the chromosome of the live attenuated Vibrio cholerae vaccine strain CVD103-HgR. Expression studies showed that the production of complete S. sonnei O-polysaccharide (O-PS)-bearing LPS was limited in bivalent recombinant strains that were also proficient in the synthesis of the host-encoded Inaba O-PS. Conversely, high amounts of LPS carrying S. sonnei O-PS are produced in monovalent Inaba-deficient derivatives, even in those strains which do not co-express the compatible R1 LPS core. Thus, the non-enterobacterial V. cholerae LPS core efficiently acts as a receptor for covalent binding of S. sonnei O-PS provided that competition with the host O-PS is avoided. Expression of the R1 core interferes with cell division in recombinant V. cholerae without affecting other physiological properties of vaccine strain CVD103-HgR. Both monovalent and bivalent strains stimulated high serum-antibody titres specific for their respective O-serotype(s) when administered to rabbits. The potential of V. cholerae as an expression carrier for heterologous O-serotypes is discussed. 相似文献
20.