全文获取类型
收费全文 | 2079篇 |
免费 | 116篇 |
国内免费 | 103篇 |
专业分类
2298篇 |
出版年
2024年 | 6篇 |
2023年 | 14篇 |
2022年 | 64篇 |
2021年 | 111篇 |
2020年 | 69篇 |
2019年 | 89篇 |
2018年 | 68篇 |
2017年 | 58篇 |
2016年 | 88篇 |
2015年 | 156篇 |
2014年 | 152篇 |
2013年 | 173篇 |
2012年 | 213篇 |
2011年 | 182篇 |
2010年 | 104篇 |
2009年 | 93篇 |
2008年 | 130篇 |
2007年 | 82篇 |
2006年 | 95篇 |
2005年 | 77篇 |
2004年 | 77篇 |
2003年 | 48篇 |
2002年 | 51篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 18篇 |
1998年 | 15篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有2298条查询结果,搜索用时 15 毫秒
71.
72.
Ross A. Robinson Samuel C. Griffiths Lieke L. van de Haar Tomas Malinauskas Eljo Y. van Battum Pavol Zelina Rebekka A. Schwab Dimple Karia Lina Malinauskaite Sara Brignani Marleen H. van den Munkhof Özge Düdükcü Anna A. De Ruiter Dianne M.A. Van den Heuvel Benjamin Bishop Jonathan Elegheert A. Radu Aricescu R. Jeroen Pasterkamp Christian Siebold 《Cell》2021,184(8):2103-2120.e31
73.
Na Song Lina Yin Dianrong Sun Linlin Zhao Tianxiang Gao 《Zeitschrift fur angewandte Ichthyologie》2019,35(3):709-718
The spinyhead croaker Collichthys lucidus (Richardson) is a small sciaenid species distributed along the inshore waters of northwestern Pacific Ocean, and now has been listed as Key Protected Commercial Sources of Aquatic Animals and Plants in China. To delineate stock boundaries and inform conservation policy for its management, samples were collected from eight locations across the Chinese coastal waters and analyzed at nine microsatellite loci. C. lucidus populations showed low genetic diversity (expected heterozygosity = 0.445–0.542; observed heterozygosity = 0.392–0.539; Polymorphism Information Content = 0.268–0.684). Strong genetic fdifferentiation (Fst = 0.065–0.510, all significant after Bonferroni correction) among all populations and high levels of self‐recruitment (89.2%–91.5%) were observed, which suggested limited genetic exchange for this species. Clustering results of discriminant analysis of principal components and STRUCTURE found strong support for obvious genetic clusters (populations FZ, XM and SZ vs. populations SH, YRE, ZS, WZ and ND). The results of the present study not only supported the phylogeographic pattern of north‐south differentiation, but also suggested that C. lucidus populations may be predominantly sustained by self‐replenishment rather than by recruitment from distant populations. 相似文献
74.
75.
Lina B. Flor-Weiler Robert W. Behle Eric T. Johnson Daniel A. Strickman Alejandro P. Rooney 《Biocontrol Science and Technology》2019,29(1):68-82
We evaluated the potential of a granular formulation of Metarhizium brunneum F52 containing microsclerotia (MbMSc granules) for control of Aedes aegypti by targeting eggs. MbMSc granules produced infective conidia within 14 days after application to 2.5?g moist potting soil, producing 5.9?×?105, 2.08?×?106 and 6.85?×?106 conidia from 1, 5 and 25?mg MbMSc granules, respectively. Application of MbMSc triggered premature eclosion of eggs (EC50?=?12?mg) with percentages as high as 31?±?2.9% and 67?±?4.3% of the eggs treated with 5 and 25?mg MbMSc granules, respectively, after 14 days on moist filter paper. Premature eclosion of eggs started at 3 days subsequent to MbMSc granule application and survival of larvae was significantly reduced for granule treated eggs (74?±?2.2%, 39?±?2.0% and 23?±?4.9% larvae survived for 1, 5 and 25?mg granule treatments, respectively, EC50?=?4.9?mg). When MbMSc granules were applied in moist potting soil with mosquito eggs, rates of 1, 5 and 25?mg of MbMSc granules significantly reduced adult emergence with only 81?±?2.1%, 47?±?1.9%, and 34?±?2.1% emergence, respectively (EC50?=?7?mg). Eggs treated with increasing concentrations of fungal conidia enhanced premature eclosion of eggs with an EC50?=?1.6?×?106 conidia/mL. Our results demonstrate that MbMSc granules are a promising candidate for control of A. aegypti and that fermentative production of Mb F52 microsclerotia as the active propagule has the potential for use for mosquito control. 相似文献
76.
77.
Two stable and water-soluble organometallic carbonyl cluster derivatives have been prepared and shown to enter the cell with ease. The CO stretching vibrations afford strong mid-infrared signals which have been demonstrated, for the first time, to be of utility in cell imaging via an IR microscope. 相似文献
78.
Romney M. Humphries Michael S. Donnenberg Jonathan Strecker Elena Kitova John S. Klassen Lina Cui Thomas P. Griener George L. Mulvey Glen D. Armstrong 《Molecular microbiology》2009,72(4):859-868
Bundle-forming pili (BFP) promote the adherence of typical enteropathogenic Escherichia coli (EPEC) to human intestinal epithelial cells. BFP are polymers of bundlin and nine bundlin alleles have been identified in EPEC isolated from diverse sources. These alleles are divided into two main groups, α and β, based on their amino acid sequences. Alpha bundlins are also N -acetyllactosamine- (LacNAc) specific lectins and bind to HEp-2 cells, whereas β bundlins do not display these characteristics. The four surface-exposed regions of amino acid sequence heterogeneity between α and β bundlin were therefore investigated as potential LacNAc-specific carbohydrate-binding domains in a bundlin. Mutation of one of these domains, 137-GENNI-141, in α1 bundlin to that of β bundlin (136-SPDST-140) resulted in BFP that no longer bound to LacNAc or HEp-2 cells. Conversely, mutating the β3 bundlin gene to encode the α bundlin sequence at this domain resulted in the gain of HEp-2 cell adherence. The importance of this domain in carbohydrate binding is supported by the finding that introducing the mutation GENNI→GENNT altered the α1 bundlin carbohydrate-binding specificity from LacNAc to the Lewis X glycan sequence. 相似文献
79.
A multi‐component catalyst Ni‐VOx/AC (VOx is comprised of V2O5 and VO2, x = 2.18) was synthesized by a wet impregnation method. The synthesized Ni‐VOx/AC shows a superior catalytic effect on de/hydrogenation of Mg. The MgH2+Ni‐VOx/AC composites can absorb 6.2 wt.‐% hydrogen within only 1 min at 150 °C under a hydrogen pressure of 2 MPa and desorb 6.5 wt.‐% hydrogen within 10 min at 300 °C under an initial hydrogen pressure of 1 KPa, which overcomes a critical barrier for practical use of Mg as a hydrogen storage material. A significant decrease of activation energy (Ea) indicates that Ni‐VOx/AC catalyst is highly efficient for Mg de/hydrogenation, which may be ascribed to the synergistic effect of bimetals (metal oxides) and nanocarbon. 相似文献
80.
Xi Jin Tianhai Lin Guang Yang Huawei Cai Bo Tang Xinyang Liao Huifang Li Xiaoting Chen Lina Gong Hang Xu Yi Sun Ping Tan Jianqiong Yin Hongwen Ma Jianzhong Ai Kunjie Wang Qiang Wei Lu Yang Hong Li 《Journal of cellular and molecular medicine》2020,24(9):5082-5096
Benign prostatic hyperplasia (BPH) occurs most commonly among older men, often accompanied by chronic tissue inflammation. Although its aetiology remains unclear, autoimmune dysregulation may contribute to BPH. Regulatory T cells (Tregs) prevent autoimmune responses and maintain immune homeostasis. In this study, we aimed to investigate Tregs frequency, phenotype, and function in BPH patients and to evaluate adoptive transfer Tregs for immunotherapy in mice with BPH via CD39. Prostate specimens and peripheral blood from BPH patients were used to investigate Treg subsets, phenotype and Treg‐associated cytokine production. Sorted CD39+/? Tregs from healthy mice were adoptively transferred into mice before or after testosterone propionate administration. The Tregs percentage in peripheral blood from BPH patients was attenuated, exhibiting low Foxp3 and CD39 expression with low levels of serum IL‐10, IL‐35 and TGF‐β. Immunohistochemistry revealed Foxp3+ cells were significantly diminished in BPH prostate with severe inflammatory. Although the Tregs subset was comprised of more effector/memory Tregs, CD39 was still down‐regulated on effector/memory Tregs in BPH patients. Before or after testosterone propionate administration, no alterations of BPH symptoms were observed due to CD39‐ Tregs in mice, however, CD39+Tregs existed more potency than Tregs to regulate prostatic hyperplasia and inhibit inflammation by decreasing IL‐1β and PSA secretion, and increasing IL‐10 and TGF‐β secretion. Furthermore, adoptive transfer with functional Tregs not only improved prostate hyperplasia but also regulated muscle cell proliferation in bladder. Adoptive transfer with Tregs may provide a novel method for the prevention and treatment of BPH clinically. 相似文献