全文获取类型
收费全文 | 120848篇 |
免费 | 2433篇 |
国内免费 | 2413篇 |
出版年
2024年 | 67篇 |
2023年 | 350篇 |
2022年 | 838篇 |
2021年 | 1417篇 |
2020年 | 972篇 |
2019年 | 1198篇 |
2018年 | 12710篇 |
2017年 | 11241篇 |
2016年 | 8494篇 |
2015年 | 2476篇 |
2014年 | 2416篇 |
2013年 | 2585篇 |
2012年 | 6738篇 |
2011年 | 14864篇 |
2010年 | 13255篇 |
2009年 | 9340篇 |
2008年 | 11174篇 |
2007年 | 12570篇 |
2006年 | 1436篇 |
2005年 | 1489篇 |
2004年 | 1760篇 |
2003年 | 1725篇 |
2002年 | 1323篇 |
2001年 | 747篇 |
2000年 | 553篇 |
1999年 | 444篇 |
1998年 | 256篇 |
1997年 | 294篇 |
1996年 | 265篇 |
1995年 | 216篇 |
1994年 | 224篇 |
1993年 | 181篇 |
1992年 | 239篇 |
1991年 | 222篇 |
1990年 | 137篇 |
1989年 | 113篇 |
1988年 | 96篇 |
1987年 | 121篇 |
1986年 | 82篇 |
1985年 | 69篇 |
1984年 | 59篇 |
1983年 | 53篇 |
1982年 | 40篇 |
1981年 | 26篇 |
1979年 | 25篇 |
1975年 | 26篇 |
1972年 | 263篇 |
1971年 | 285篇 |
1965年 | 22篇 |
1962年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Sun QiangLing Liu YinKun Lu WenJing Cheng Gang Zhou HaiJun Zhou XinWen Wei LiMing Dai Zhi Guo Kun Lu HaoJie 《中国科学C辑(英文版)》2007,50(3):403-411
In order to establish the novel high throughput, high efficiency and low cost technological platform for the research of N-glycoproteomics, to resolve the significance of characteristic expression profile of glycoprotein and to find the proteins
with biological functional importance, the glycoproteins with high-mannose core and the two antennary types were purified
and enriched by the Con A affinity chromatography. Con A affinity protein expression profiles of normal human liver tissue
were generated by using SDS-PAGE, two-dimensional electrophoresis (2-DE) followed by fast fluorescence staining based on multiplexed
proteomics (MP) technology. 301 visible protein spots on the gel were detected and 85 of glycoproteins were further successfully
identified via peptide mass fingerprinting (PMF) by a matrix assisted laser desorption/ionization time-of-flight mass spectrometry
(MALDI-TOF-MS/MS) and annotated to IPI databases. Identified glycoproteins definitely take part in the regulation of cell
cycle and metabolic processes. The glycosylation sites were predicted with NetNGlyc 1.0 and NetOGlyc 3.1 software, meanwhile
they were classified according to the geneontology methods. The construction of Con A affinity glycoprotein database of normal
human liver tissue would contribute to the subsequent research. 相似文献
992.
5-羟色胺(5-hydroxytryptamine, 5-HT)是生物界广泛分布的信号分子,涉及动物的重要行为。5-HT是色氨酸羟化酶(Tryptophan hydroxylase, TRH)将L-色氨酸羟化为5-羟-L-色氨酸,5-羟-L-色氨酸随即被多巴脱羧酶(Aromatic L-amino acid decarboxylase, DDC)脱羧而成。TRH作为5-HT合成的限速酶,在无脊椎动物神经调控中具有重要地位。鳞翅目昆虫中TRH的功能研究并不多。在家蚕中克隆了家蚕TRH (Bombyx mori TRH, BmTRH)的cDNA序列1667bp,其中包含1632bp的开放读码框(Openreadingframe,ORF)。人类TPH或者果蝇TRH(Drosophila TRH, DmTRH)与BmTRH有高度相似性,尤其BmTRH和DmTRH之间大多数氨基酸保守说明它们在系统发育上的密切关系并可能有相似功能。基因表达分析显示BmTRH主要表达于头部和中枢神经组织,免疫组织化学和Western blotting结果显示BmTRH只存在于神经组织中,即BmTRH可能仅参与家蚕的神经活动。此外,家蚕DDC(B.moridecarboxylase,BmDDC)和蛋白具有TRH活性的苯丙氨酸羟化酶基因(Phenylalanine hydroxylase, BmPAH)也在中枢神经系统中有表达,暗示家蚕神经系统5-HT的合成与果蝇中不同,可能有两种不同的调控机制。 相似文献
993.
Cindy Q. Tang Mei-Hua Zhao Xiao-Shuang Li Masahiko Ohsawa Xiao-Kun Ou 《Ecological Research》2010,25(1):149-161
Since 1985, originally forested mountainous areas of China have been allowed to return to their natural state after years
of exploitation including agriculture, development, and logging. The reforms began earlier in less accessible locations, so
that today the successional process is more advanced there. The vegetation in Luquan, Qiongzhusi, and Xishan near Kunming,
central Yunnan, exhibits, in a limited area, a range of stages of plant succession that are widely encountered throughout
the broader region, and thus affords a special opportunity for a comprehensive study. We analyzed the successional sequence
of these various plant communities. They ranged from pioneer coniferous and/or pioneer deciduous broad-leaved stands to pre-mature
semi-humid evergreen broad-leaved stands, through mixed coniferous and broad-leaved or mixed deciduous and evergreen broad-leaved
stands. The succession proceeded from pioneer coniferous Pinus and Keteleeria, and deciduous Platycarya and Alnus, to late-successional evergreen broad-leaved Cyclobalanopsis and Castanopsis. Two regeneration types of woody species in either the early successional (15–50 years), the mid-successional (40–80 years),
or the late-successional (80–180 years) stage were classified. Relatively high species diversity was found in the seral phase
at the three study sites. The late-successional stage was commonest where human disturbance was least evident. Poor soil chemical
properties under pioneer Pinus were seen as a limitation to plant growth, while the abundance of Alnus at the early stage led to an improved level of organic matter and nitrogen. 相似文献
994.
Background
Non-invasive planar fluorescence reflectance imaging (FRI) is used for accessing physiological and molecular processes in biological tissue. This method is efficiently used to detect superficial fluorescent inclusions. FRI is based on recording the spatial radiance distribution (SRD) at the surface of a sample. SRD provides information for measuring structural parameters of a fluorescent source (such as radius and depth). The aim of this article is to estimate the depth and radius of the source distribution from SRD, measured at the sample surface. For this reason, a theoretical expression for the SRD at the surface of a turbid sample arising from a spherical light source embedded in the sample, was derived using a steady-state solution of the diffusion equation with an appropriate boundary condition. 相似文献995.
996.
We tested the pathogenicity of 18 Metarhizium anisopliae (Metschn.) Sorokin isolates and 22 Beauveria bassiana (Balsamo) Vuillemin isolates against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) larvae and adults. The efficacy of the most virulent isolate—M. anisopliae K—was evaluated in containers with a concrete bottom covered with wood shavings, under simulated poultry house conditions.
Application of conidia of this isolate to the shavings or directly to the concrete bottom reduced the yield of larvae in 8–15
time compared with the control. In another test, the mortality of mature larvae placed on previously inoculated shavings or
bottom reached 80–90% within 14 days, compared with 14% in the control. The residual activity of conidia kept at 28°C retained
its initial level during 14 days post-inoculation, but declined after three weeks. Based on our data M. anisopliae has considerable potential for the control of A. diaperinus.
相似文献
Michael SamishEmail: Email: |
997.
998.
Li J Sun L Xu C Yu F Zhou H Zhao Y Zhang J Cai J Mao C Tang L Xu Y He J 《生物化学与生物物理学报(英文版)》2012,44(4):300-306
The activation of molecular chaperone heat-shock protein 90 (Hsp90) is dependent on ATP binding and hydrolysis, which occurs in the N-terminal domains of protein. Here, we have determined three crystal structures of the N-terminal domain of human Hsp90 in native and in complex with ATP and ATP analog, providing a clear view of the catalytic mechanism of ATP hydrolysis by Hsp90. Additionally, the binding of ATP leads the N-terminal domains to be an intermediate state that could be used to partially explain why the isolated N-terminal domain of Hsp90 has very weak ATP hydrolytic activity. 相似文献
999.
1000.
Yuanyuan Yu Jiugang Yuan Qiang Wang Xuerong Fan Ping Wang Xuejiao Sun 《Engineering in Life Science》2013,13(2):194-200
Cellulases can penetrate into the fiber, causing tensile strength loss of the cellulosic fibers or fabrics. To minimize the tensile strength loss, we have immobilized cellulases on Eudragit S‐100. The characteristics of covalent Eudragit cellulase were evaluated using gel filtration analysis and UV spectra. Gel filtration analysis revealed that the cellulases were covalently bound to the polymer. Covalent Eudragit cellulase was loaded with the enzyme of about 40% and had a relative activity about 80% at a Eudragit S‐100 concentration of 15 g/L. When cellulase is bound to the polymer, the solubility profile becomes similar to the one of Eudragit. In addition, the effects of the enzyme on the cotton yarns and fabric using cellulases have been investigated. Native and immobilized cellulases caused improvements in whiteness and wrinkle recovery angle of the fabric in comparison to the control samples. The bending stiffness results show that native and immobilized cellulase treated cotton fabric has an improved softness than the control samples. It was found that using the immobilized cellulase reduced the weight and tensile strength, because the hydrolytic attack is only limited to the surfaces of cotton fibers. 相似文献