全文获取类型
收费全文 | 6311篇 |
免费 | 466篇 |
国内免费 | 2篇 |
出版年
2022年 | 26篇 |
2021年 | 69篇 |
2020年 | 37篇 |
2019年 | 34篇 |
2018年 | 95篇 |
2017年 | 60篇 |
2016年 | 122篇 |
2015年 | 194篇 |
2014年 | 232篇 |
2013年 | 271篇 |
2012年 | 506篇 |
2011年 | 501篇 |
2010年 | 209篇 |
2009年 | 201篇 |
2008年 | 384篇 |
2007年 | 354篇 |
2006年 | 413篇 |
2005年 | 359篇 |
2004年 | 359篇 |
2003年 | 334篇 |
2002年 | 316篇 |
2001年 | 169篇 |
2000年 | 195篇 |
1999年 | 116篇 |
1998年 | 57篇 |
1997年 | 48篇 |
1996年 | 53篇 |
1995年 | 37篇 |
1994年 | 51篇 |
1993年 | 46篇 |
1992年 | 65篇 |
1991年 | 51篇 |
1990年 | 53篇 |
1989年 | 61篇 |
1988年 | 41篇 |
1987年 | 40篇 |
1986年 | 37篇 |
1985年 | 37篇 |
1984年 | 34篇 |
1983年 | 34篇 |
1982年 | 31篇 |
1981年 | 25篇 |
1980年 | 27篇 |
1979年 | 30篇 |
1978年 | 38篇 |
1977年 | 35篇 |
1976年 | 32篇 |
1975年 | 24篇 |
1974年 | 25篇 |
1973年 | 35篇 |
排序方式: 共有6779条查询结果,搜索用时 31 毫秒
1.
2.
Ildikó Vidra Kálmán Simon László Institóris Ingeborg Csöregh Mátyás Czugler 《Carbohydrate research》1982,111(1):41-57
After hydrolysis of 1,6-dibromo-1,6-dideoxygalactitol (1) and 1,2:5,6-dianhydrogalactitol (2), 11 compounds were isolated, three of them as tritylated derivatives. Their structures were established on the basis of chemical evidence and, for four compounds, by X-ray diffraction. The main product of the hydrolysis of 1 was 3,6-anhydro-1-bromo-1-deoxy-dl-galactitol; the end-products of the hydrolysis of 2 were 1,5-anhydro-dl-galactitol, 2,5-anhydro-dl-altritol, and galactitol. 相似文献
3.
The build-up of neurosecretory material in the median neurosecretory cells and fibre tracts of cultured cockroach brains was demonstrated by staining and bioassay. Examination of the cultured brains by electron microscopy showed active production of neurosecretory granules after 3 days in vitro. The close correlation of the results obtained by these different methods of assay leaves little doubt that a neurohormone is being synthesized and stored. 相似文献
4.
The biodistribution and pharmacokinetics of vanadium following i.p. administration of vanadocene dichloride (VDC), a representative of a new class of organometallic anticancer agents, is reported for Strain A mice. A convenient flameless atomic absorption spectroscopic assay is described and is used to determine kinetic profiles for vanadium in blood, kidney, liver, small intestine and brain tissue for times up to 24 h after administration. For a VDC dose of 80 mg/kg, vanadium concentration decreases rapidly from both the blood and small intestine, and the data can be fit to a phenomenological exponential function (blood: t1/2 = 118 +/- 43 min; small intestine: t1/2(alpha) = 18.10 +/- 0.14 min, t1/2(beta) = 341 +/- 45 min). In contrast, vanadium accumulates in both the kidney and liver up to a maximal concentration (1.12 +/- 0.06 mM and 0.56 +/- 0.06 mM after 12 and 8 h, respectively), and is then excreted with estimated half-lives of 7.9 +/- 0.7 and 12.1 +/- 0.1 h, respectively. No detectable levels of vanadium are found in the brain tissue over the temporal course of the experiment. These results are compared to previous mammalian studies with cis-dichlorodiammineplatinum(II) (CDDP) and related 'second generation' platinum derivatives; there are both qualitative similarities between the vanadium and platinum systems as well as important quantitative differences. 相似文献
5.
6.
Christian Renz Silke Oeljeklaus S?ren Grinhagens Bettina Warscheid Nils Johnsson Thomas Gronemeyer 《PloS one》2016,11(2)
The septins are a conserved family of GTP-binding proteins that, in the baker''s yeast, assemble into a highly ordered array of filaments at the mother bud neck. These filaments undergo significant structural rearrangements during the cell cycle. We aimed at identifying key components that are involved in or regulate the transitions of the septins. By combining cell synchronization and quantitative affinity-purification mass-spectrometry, we performed a screen for specific interaction partners of the septins at three distinct stages of the cell cycle. A total of 83 interaction partners of the septins were assigned. Surprisingly, we detected DNA-interacting/nuclear proteins and proteins involved in ribosome biogenesis and protein synthesis predominantly present in alpha-factor arrested that do not display an assembled septin structure. Furthermore, two distinct sets of regulatory proteins that are specific for cells at S-phase with a stable septin collar or at mitosis with split septin rings were identified.Complementary methods like SPLIFF and immunoprecipitation allowed us to more exactly define the spatial and temporal characteristics of selected hits of the AP-MS screen. 相似文献
7.
8.
Oat (Avena sativa L.) mesophyll protoplasts were recently demonstrated to be capable of dedifferentiation, repeated divisions, and colony formation. Since the development of oat mesophyll protoplasts is decisively influenced by the nature of the used feeder culture (species, variety and concentration), we conducted a systematic study of this parameter. Generally, graminaceous feeders promoted protoplast proliferation, while dicot species repressed protoplast divisions. The beneficial effect of those feeders that promote divisions was counterbalanced by a factor that causes necrosis. The correct balance between promotion of divisions or necrosis depended on the nature of the feeder and its plating density. 相似文献
9.
10.