全文获取类型
收费全文 | 11781篇 |
免费 | 2175篇 |
国内免费 | 1169篇 |
出版年
2024年 | 79篇 |
2023年 | 430篇 |
2022年 | 400篇 |
2021年 | 613篇 |
2020年 | 625篇 |
2019年 | 625篇 |
2018年 | 533篇 |
2017年 | 556篇 |
2016年 | 521篇 |
2015年 | 528篇 |
2014年 | 625篇 |
2013年 | 829篇 |
2012年 | 543篇 |
2011年 | 577篇 |
2010年 | 503篇 |
2009年 | 620篇 |
2008年 | 625篇 |
2007年 | 639篇 |
2006年 | 553篇 |
2005年 | 502篇 |
2004年 | 448篇 |
2003年 | 437篇 |
2002年 | 378篇 |
2001年 | 303篇 |
2000年 | 249篇 |
1999年 | 267篇 |
1998年 | 228篇 |
1997年 | 191篇 |
1996年 | 190篇 |
1995年 | 156篇 |
1994年 | 151篇 |
1993年 | 127篇 |
1992年 | 107篇 |
1991年 | 110篇 |
1990年 | 87篇 |
1989年 | 88篇 |
1988年 | 80篇 |
1987年 | 66篇 |
1986年 | 56篇 |
1985年 | 64篇 |
1984年 | 72篇 |
1983年 | 47篇 |
1982年 | 61篇 |
1981年 | 47篇 |
1980年 | 33篇 |
1979年 | 24篇 |
1978年 | 36篇 |
1977年 | 28篇 |
1976年 | 19篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A. A. Kepel' 《Russian Journal of Marine Biology》2000,26(6):450-452
The alga Analipus japonicus (Harv.) Wynne displays a distinct seasonal pattern in its development in Peter the Great Bay (Sea of Japan). In winter and spring, it occurs only in the form of basal crusts, and vertical axes develop in the summer–autumn period. It reproduces mostly asexually from July to November. Algae with unilocular sporangia occur very seldom, only in June and July. 相似文献
2.
《Cell reports》2020,30(4):1152-1163.e4
- Download : Download high-res image (170KB)
- Download : Download full-size image
3.
This paper is concerned with gene survival in a population which may increase without density dependence according to a generalization of the Moran model for haploid individuals. A selective advantage to one allele and the possibility of differential reproductive rates are allowed. Simple conditions are given for ultimate homozygosity to be certain and for the possibility of ultimate polymorphism. The results complement and extend those of Heyde (1981, 1982). 相似文献
4.
Ting Zhang Bai‐Ge Miao Bo Wang Yan‐Qiong Peng Clive T. Darwell 《Ecological Entomology》2019,44(6):844-848
1. Species interactions in tightly bound ecological mutualisms often feature highly specialised species' roles in which competitive exclusion may preclude multi‐species coexistence. Among the 800 fig (Ficus) species, it was originally considered that each was pollinated by their own wasp (Agaonidae). However, recent investigations show that this ‘one‐to‐one’ rule often breaks down, as fig species regularly host multiple agaonids but in ways suggesting that competitive processes still mediate biodiversity outcomes. 2. A phenological survey was conducted of the fig–fig wasp pair, Ficus microcarpa and its associated pollinating wasp, alongside its sister species, the cheating wasp, in Xishuangbanna, China. 3. Reproductive output underwent extreme seasonal variation. Seed and pollinator production fell markedly during cooler, drier months, although high levels of fig production continued. However, this resource was predominantly utilised by the cheater species, which offers no pollination services. Pollinators and cheaters rarely co‐occur, suggesting that temporal coexistence is constrained by competition for access to figs. 4. The overall findings indicate periodic rearrangements of mutualism dynamics, probably resulting from a strongly seasonal environment. Sympatric co‐occurrence may result from a window of opportunity for a functionally divergent agaonid, potentially due to constraints on the main pollinator in adapting to variable year‐round conditions that prevent competitive exclusion. 相似文献
5.
T. J. Wojciechowski 《Biometrical journal. Biometrische Zeitschrift》1987,29(8):953-959
In this paper very simple nonparametric classification rule for mixtures of discrete and continuous random variables is described. It is based on the method of nearest neighbor proposed by Cover and Hart (1967). The bounds on the limit of the nearest neighbor rule risks are given. Both lower and upper bound depend on the Bayes risk and the loss function. Finally the method is compared with other existing methods on some practical data set. 相似文献
6.
《Molecular & cellular proteomics : MCP》2020,19(7):1161-1178
- Download : Download high-res image (250KB)
- Download : Download full-size image
- •XL-MS reveals new PPIs in yeast mitochondria under glycerol and glucose condition.
- •Significant but limited results from quantitative XL-MS experiments.
- •Ndi1 participates in a CIII2CIV2 respiratory supercomplex.
- •Min8 promotes assembly of Cox12 into an intermediate complex IV.
7.
《Molecular & cellular proteomics : MCP》2020,19(1):142-154
- Download : Download high-res image (133KB)
- Download : Download full-size image
- •Flow cytometry analysis is used to isolate ASC speck(+) NPC cells.
- •Proteome analysis of ASC speck(+) NPC cells reveals enriched mitochondrial OxPhos proteins.
- •OxPhos proteins mediate NLRP3 inflammasome activation through mtROS.
- •OxPhos proteins, NDUFB8 and ATP5B are correlated with NPC local recurrence.
8.
9.
N-糖蛋白去糖基化酶(PNGase)是一种广泛存在于真菌、植物、哺乳动物中的去糖基化酶,可以水解N-糖蛋白或 N-糖肽上天冬酰胺与寡糖链连接的化学键,并释放出完整的N-寡糖。PNGase在生物体内参与蛋白质降解、器官发育、个体生长等过程。人PNGase基因功能缺陷会导致先天性去糖基化障碍,小鼠PNGase缺陷会导致胚胎致死性,线虫PNGase缺陷使其寿命下降。本文对PNGase在不同物种的分布、蛋白质结构、酶学功能及生物学功能进行阐述,为PNGase的生理病理功能及致病机制的基础研究提供思路,为PNGase作为糖生物学工具酶或药物开发的创新应用研究奠定基础。 相似文献
10.
Dominant males of nonseasonally breeding species should have more opportunity than seasonal breeders to monopolize access to estrous females and thus enhance their reproductive success. They may also use other strategies for maximizing reproductive success such as producing offspring by relatively high ranking females. To test these hypotheses, the paternity of 35 (80%) of 44 Macaca fascicularis offspring, born over a 28-month period, was established using electrophoretically and serologically defined genetic markers. The social ranks of each of the seven potential fathers and 26 potential mothers were determined by recording outcomes of dyadio agonistic interactions. No evidence could be found to support either hypothesis. Further, in view of previously reported significant, positive correlations between male social rank and sexual activity rates in this study group, sexual activity rates do not appear to predict the number of offspring a male sires in this species. 相似文献