全文获取类型
收费全文 | 9723篇 |
免费 | 578篇 |
国内免费 | 1篇 |
出版年
2023年 | 82篇 |
2021年 | 137篇 |
2020年 | 113篇 |
2019年 | 129篇 |
2018年 | 417篇 |
2017年 | 357篇 |
2016年 | 416篇 |
2015年 | 316篇 |
2014年 | 439篇 |
2013年 | 727篇 |
2012年 | 751篇 |
2011年 | 801篇 |
2010年 | 515篇 |
2009年 | 336篇 |
2008年 | 284篇 |
2007年 | 234篇 |
2006年 | 263篇 |
2005年 | 97篇 |
2004年 | 95篇 |
2003年 | 97篇 |
2002年 | 78篇 |
2001年 | 104篇 |
2000年 | 116篇 |
1999年 | 129篇 |
1998年 | 103篇 |
1997年 | 98篇 |
1996年 | 99篇 |
1995年 | 120篇 |
1994年 | 98篇 |
1993年 | 75篇 |
1992年 | 96篇 |
1991年 | 112篇 |
1989年 | 76篇 |
1988年 | 79篇 |
1987年 | 85篇 |
1985年 | 104篇 |
1984年 | 90篇 |
1983年 | 106篇 |
1982年 | 92篇 |
1981年 | 109篇 |
1980年 | 79篇 |
1979年 | 96篇 |
1978年 | 80篇 |
1977年 | 78篇 |
1976年 | 71篇 |
1975年 | 76篇 |
1974年 | 76篇 |
1973年 | 71篇 |
1972年 | 70篇 |
1969年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
Ruth Duncan Pavla Rejmanova Jindrich Kopeček John B. Lloyd 《Biochimica et Biophysica Acta (BBA)/General Subjects》1981,678(1):143-150
Synthetic 125I-labelled N-(2-hydroxypropyl)methacrylamide copolymers containing four different, potentially degradable peptidyl side chains were incubated with rat visceral yolk sacs cultured in vitro. All copolymers were captured by fluid-phase pinocytosis and three of the side chains were susceptible to lysosomal hydrolysis, resulting in release of [125I]iodotyrosine back into the culture medium. Uptake and degradation was completely inhibited by 2,4-dinitrophenol. The thiol-proteinase inhibitor leupeptin did not affect the rate of pinocytosis, but caused different degrees of inhibition of hydrolysis depending on side chain composition. 相似文献
12.
13.
Hilda Ritter-Studnička 《Plant Systematics and Evolution》1958,105(4):285-292
Zusammenfassung In der vorliegenden Arbeit wurden Pflanzenarten besprochen, die selten oder neu für das Gebiet Bosniens und der Herzegowina, und meist von allgemeinem pflanzengeographischem Interesse sind. Einige dieser Funde wurden auf Dolomit oder Serpentinunterlage festgestellt, von welchen auch einige neue Sippen beschrieben wurden. 相似文献
14.
Marie Lipoldová Helena Havelková Jana Badalová Jarmila Vojtíšková Lei Quan Magdaléna Krulová Yahya Sohrabi Alphons P. Stassen Peter Demant 《Cancer immunology, immunotherapy : CII》2010,59(2):203-213
Low infiltration of lymphocytes into cancers is associated with poor prognosis, but the reasons why some patients exhibit
a low and others a high infiltration of tumors are unknown. Previously we mapped four loci (Lynf1–Lynf4) controlling lymphocyte infiltration of mouse lung tumors. These loci do not encode any of the molecules that are involved
in traffic of lymphocytes. Here we report a genetic relationship between these loci and the control of production of IFNγ
in allogeneic mixed lymphocyte cultures (MLC). We found that IFNγ production by lymphocytes of O20/A mice is lower than by
lymphocytes of OcB-9/Dem mice (both H2
pz
) stimulated in MLC by irradiated splenocytes of C57BL/10SnPh (H2
b
) or BALB/cHeA (H2
d
) mice, or by ConA. IFNγ production in MLCs of individual (O20 × OcB-9)F2 mice stimulated by irradiated C57BL/10 splenocytes and genotyped for microsatellite markers revealed four IFNγ-controlling
loci (Cypr4-Cypr7), each of which is closely linked with one of the four Lynf loci and with a cluster of susceptibility genes for different tumors. This suggests that inherited differences in certain
lymphocyte responses may modify their propensity to infiltrate tumors and their capacity to affect tumor growth. 相似文献
15.
16.
M. Konečná 《Zeitschrift fur angewandte Ichthyologie》2012,28(5):806-810
This study focuses on assessing the reproduction mode of an important model species for evolutionary and behavioural ecology by using digital image analysis: the European bitterling Rhodeus amarus (Bloch, 1782). Specifications of mode of reproduction were determined using oocyte size distribution, seasonal dynamics in mean oocyte diameter and total number of oocytes in ovary samples gained from April to July 2007. The rapid oocyte count was enabled by using lucia image analysis software, which also provided measurement and colour estimations of oocytes. Bitterling ovaries showed features typical for indeterminate spawners, i.e. a continuous distribution of oocyte size over the reproductive season and recruitment of new pre‐vitelogenic oocytes in the second half of the reproductive season. These results are consistent with the view that the European bitterling is a batch spawning fish with indeterminate fecundity. 相似文献
17.
J. Nečas 《Biologia Plantarum》1970,12(5):359-367
Populations of theChloretta vulgaris Beijeb. strain ?esnokov “V” clones (progenies of single cells) grown up from cells treated by chemical mutagens were cultivated on the surface of solid media. The differentiation of growth types according to their growth rates in the populations originating from the same sample of cells but growing under different conditions was compared. The strain studied exhibited much greater growth rate variability on the complete medium than on the minimal one. Short time changes of light regime during the cultivation for the purpose of inducing reparation processes in the mutagen damaged cells did not manifest themselves significantly in the composition of resulting clonal populations. The possibility of selection of growth types under conditions studied was considered. 相似文献
18.
In vitro as well as in vivo evaluation of the reactivating efficacy of various oximes against nerve agent-inhibited acetylcholinesterase has been usually done with the help of animal experiments. Nevertheless, previously published data indicate that the reactivation potency of oximes may be different in human and animal species, which may hamper the extrapolation of animal data to human data. Therefore, to better evaluate the efficacy of various oximes (pralidoxime, obidoxime, HI-6, K033) to reactivate brain acetylcholinesterase inhibited by sarin by in vitro methods, human, rat and pig brain acetylcholinesterase were used to calculate kinetic parameters for the reactivation. Our results show differences among the species, depending on the type of oxime, and indicate that data from animal experiments needs to be carefully evaluated before extrapolation to humans. 相似文献
19.
20.
Algirdas Mikalkėnas Bazilė Ravoitytė Daiva Tauraitė Elena Servienė Rolandas Meškys 《Journal of enzyme inhibition and medicinal chemistry》2018,33(1):384-389
Small molecule inhibitors have a powerful blocking action on viral polymerases. The bioavailability of the inhibitor, nevertheless, often raise a significant selectivity constraint and may substantially limit the efficacy of therapy. Phosphonoacetic acid has long been known to possess a restricted potential to block DNA biosynthesis. In order to achieve a better affinity, this compound has been linked with natural nucleotide at different positions. The structural context of the resulted conjugates has been found to be crucial for the acquisition by DNA polymerases. We show that nucleobase-conjugated phosphonoacetic acid is being accepted, but this alters the processivity of DNA polymerases. The data presented here not only provide a mechanistic rationale for a switch in the mode of DNA synthesis, but also highlight the nucleobase-targeted nucleotide functionalization as a route for enhancing the specificity of small molecule inhibitors. 相似文献