全文获取类型
收费全文 | 74162篇 |
免费 | 6088篇 |
国内免费 | 1122篇 |
专业分类
81372篇 |
出版年
2023年 | 493篇 |
2022年 | 1153篇 |
2021年 | 1952篇 |
2020年 | 1372篇 |
2019年 | 1570篇 |
2018年 | 2026篇 |
2017年 | 1548篇 |
2016年 | 2477篇 |
2015年 | 3483篇 |
2014年 | 3603篇 |
2013年 | 4333篇 |
2012年 | 5181篇 |
2011年 | 4695篇 |
2010年 | 2889篇 |
2009年 | 2703篇 |
2008年 | 3348篇 |
2007年 | 3185篇 |
2006年 | 2871篇 |
2005年 | 3098篇 |
2004年 | 2934篇 |
2003年 | 2504篇 |
2002年 | 2050篇 |
2001年 | 1819篇 |
2000年 | 1687篇 |
1999年 | 1534篇 |
1998年 | 752篇 |
1997年 | 678篇 |
1996年 | 699篇 |
1995年 | 571篇 |
1994年 | 545篇 |
1993年 | 508篇 |
1992年 | 1031篇 |
1991年 | 934篇 |
1990年 | 862篇 |
1989年 | 832篇 |
1988年 | 819篇 |
1987年 | 742篇 |
1986年 | 687篇 |
1985年 | 668篇 |
1984年 | 607篇 |
1983年 | 466篇 |
1982年 | 360篇 |
1981年 | 348篇 |
1980年 | 325篇 |
1979年 | 458篇 |
1978年 | 379篇 |
1977年 | 317篇 |
1975年 | 313篇 |
1974年 | 312篇 |
1973年 | 306篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
91.
92.
Wenjun Geng Jinggong Xiangyu Xiuzhen Li Zhongning Zhang Deyuan Han Yongwei Li 《Insect Science》1997,4(4):364-368
Abstract Field trials by sex pheromone of aphid to trap peach aphids Myzus persicae have been carried out in 1995 and in 1996. Suitable time and the effect of ratio of two components nepetalactone and nepetalactol to apply the lure have been observed. 相似文献
93.
An interspecific somatic hybrid between Actinidia chinensis and Actinidia kolomikta and its chilling tolerance 总被引:2,自引:0,他引:2
Protoplasts isolated from cotyledon-derived callus of Actinidia chinensisPlanch. var. chinensis (2N=2x=58) were fused with mesophyll protoplasts of Actiniadia kolomikta(Maxim. et Rupr.) Maxim (2N=2x=58) using a PEG method. Plantlets were regenerated from the fusion product clone 11. RAPD analyses, chromosome numbers of root tip cells and fluorescence peak position of leaf nuclei confirmed that clone 11 was an interspecific somatic hybrid (2N=4x=116) between A. chinensis and A. kolomikta. The chilling tolerance of the somatic hybrid was tested with in vitro leaves at low temperatures. Based on data of leaf thickness, electroconductivity, proline levels, malondialdehyde content and activity of superoxide dismutase, dendrogram cluster analysis suggested that the interspecific somatic hybrid was similar to A. kolomikta, and might have a higher capacity of cold resistance than A. chinensis. 相似文献
94.
95.
96.
Monoclonal anti-mouse macrophage antibodies recognize the globular portions of C1q, a subcomponent of the first component of complement 总被引:1,自引:0,他引:1
H P Heinz H Dlugonska E Rüde M Loos 《Journal of immunology (Baltimore, Md. : 1950)》1984,133(1):400-404
One of seven monoclonal antibodies generated against mouse macrophages (M phi) was found to recognize isolated heterologous C1q. This antibody was shown to be cytotoxic and to react in a strain-independent way with mouse M phi derived from bone marrow cells as well as with M phi from the peritoneal cavity; it did not react, however, with mouse granulocytes, thymocytes, or T and B lymphocytes. The hemolytic activity of fluid phase C1q was inhibited to 50% at a 2 X 10(-4) dilution of hybridoma supernatant, whereas a 100-fold higher concentration was required to inhibit C1q bound to immune complexes ( EAC1q ) to the same extent. It was demonstrated that this antibody recognizes the isolated globular, Fc-binding portions of the C1q molecule and reacts with the A and B chains. Because M phi have been shown to synthesize C1q, the Fc-recognizing subcomponent of the first component of complement, evidence was provided that endogeneous C1q can serve as an Fc receptor on M phi during secretion. This fact was demonstrated by a dose-dependent inhibition of Fc-receptor activity for EIgG by the F(ab')2 fragment of this monoclonal antibody. These experiments further support the concept that C1q produced by M phi functions on the surface as an Fc-recognizing molecule before it is released and incorporated into the macromolecular complex of serum C1. 相似文献
97.
Background
Chow and Liu showed that the maximum likelihood tree for multivariate discrete distributions may be found using a maximum weight spanning tree algorithm, for example Kruskal's algorithm. The efficiency of the algorithm makes it tractable for high-dimensional problems. 相似文献98.
Yanyan Han Elfriede Eppinger Ingrid G. Schuster Luise U. Weigand Xiaoling Liang Elisabeth Kremmer Christian Peschel Angela M. Krackhardt 《The Journal of biological chemistry》2009,284(48):33409-33417
The formin protein formin-like 1 (FMNL1) is highly restrictedly expressed in hematopoietic lineage-derived cells and has been previously identified as a tumor-associated antigen. However, function and regulation of FMNL1 are not well defined. We have identified a novel splice variant (FMNL1γ) containing an intron retention at the C terminus affecting the diaphanous autoinhibitory domain (DAD). FMNL1γ is specifically located at the cell membrane and cortex in diverse cell lines. Similar localization of FMNL1 was observed for a mutant lacking the DAD domain (FMNL1ΔDAD), indicating that deregulation of autoinhibition is effective in FMNL1γ. Expression of both FMNL1γ and FMNL1ΔDAD induces polarized nonapoptotic blebbing that is dependent on N-terminal myristoylation of FMNL1 but independent of Src and ROCK activity. Thus, our results describe N-myristoylation as a regulative mechanism of FMNL1 responsible for membrane trafficking potentially involved in a diversity of polarized processes of hematopoietic lineage-derived cells. 相似文献
99.