全文获取类型
收费全文 | 18234篇 |
免费 | 1462篇 |
国内免费 | 1810篇 |
出版年
2024年 | 42篇 |
2023年 | 190篇 |
2022年 | 454篇 |
2021年 | 783篇 |
2020年 | 588篇 |
2019年 | 727篇 |
2018年 | 674篇 |
2017年 | 526篇 |
2016年 | 676篇 |
2015年 | 1085篇 |
2014年 | 1289篇 |
2013年 | 1386篇 |
2012年 | 1684篇 |
2011年 | 1553篇 |
2010年 | 963篇 |
2009年 | 930篇 |
2008年 | 1024篇 |
2007年 | 892篇 |
2006年 | 791篇 |
2005年 | 717篇 |
2004年 | 575篇 |
2003年 | 527篇 |
2002年 | 476篇 |
2001年 | 339篇 |
2000年 | 314篇 |
1999年 | 259篇 |
1998年 | 220篇 |
1997年 | 161篇 |
1996年 | 157篇 |
1995年 | 148篇 |
1994年 | 149篇 |
1993年 | 118篇 |
1992年 | 133篇 |
1991年 | 114篇 |
1990年 | 117篇 |
1989年 | 94篇 |
1988年 | 79篇 |
1987年 | 74篇 |
1986年 | 53篇 |
1985年 | 63篇 |
1984年 | 41篇 |
1983年 | 42篇 |
1982年 | 34篇 |
1981年 | 22篇 |
1980年 | 20篇 |
1979年 | 23篇 |
1977年 | 18篇 |
1974年 | 16篇 |
1972年 | 17篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
851.
Nian Wei Yan Zhang Fan Wu Ziwei Shen Huijun Ru Ling Liu Zhaohui Ni 《Zeitschrift fur angewandte Ichthyologie》2019,35(3):789-792
The length–weight relationships (LWRs) for 15 fish species from the Three Gorges Reservoir (TGR) were described in this paper. Specimens were collected using gill nets (mesh size: 6, 8, 10, 12 cm), cage net (mesh size: 1 cm), benthic fyke net (mesh size: 1 cm), hook longlines (80 m long, 3 barbless hooks per meter line) and electrofishing (power: 1,500 w; distance of electrodes: 1–2 m; water depth: 0.2–1.0 m; water area: 1–2 m2; catch by dip net [mesh size: 0.4 cm]) at four sections of the TGR, monthly in June–August and October–November in 2017 and 2018. The first LWR reference for Zacco acutipinnis (Bleeker, 1871), Discogobio brachyphysallidos Huang, 1989, Squalidus nitens (Günther, 1873), Leptobotia pellegrini Fang, 1936, Sinibotia reevesae (Chang, 1944), Pseudobagrus tenuifurcatus (Nichols, 1931), Pseudobagrus medianalis (Regan, 1904), Liobagrus marginatoides (Wu, 1930), Glyptothorax fokiensis (Rendahl, 1925), and Ctenogobius szechuanensis (Liu, 1940) and new maximum total length for 12 species are provided. 相似文献
852.
853.
Transcriptome analysis of the endometrium from Chinese Erhualian sows that differ in calcium ion concentration and litter size 总被引:1,自引:0,他引:1
X. Ma P. Li Q. Zhang L. He G. Su Y. Huang Z. Lu W. Hu H. Ding R. Huang 《Animal genetics》2019,50(4):326-333
Embryonic survival rate, an important factor in the fecundity of sows, is affected by endometrium‐secreting histotroph. A higher concentration of calcium ion has been observed in the uterus of highly prolific Erhualian sows (EH) compared with those of less prolific (EL) sows. This suggests that EH sows have better establishment and maintenance of pregnancies, thus increasing embryonic survival rate during the peri‐implantation period. To understand the mechanisms of how the endometrium‐secreting histotroph affects embryonic survival rate during the Erhualian peri‐implantation period, the expression patterns of endometrial mRNA in the EH and EL sows on day 12 of gestation were analyzed using RNA sequencing technology. A total of 164 differentially expressed genes (DEGs) were identified (Padj < 0.05, |log2(FC)| ≥ 1), including 46 upregulated and 118 downregulated genes in EH compared to EL. Gene Ontology enrichment indicated that a subset of DEGs was involved in calcium ion binding and cell adhesion. Solute carrier family 8 member A3 and solute carrier family 24 member 4, identified as upregulated genes (Padj < 0.05) in EH, were considered key candidate genes expressed in the endometrium affecting embryonic survival rate during the peri‐implantation period. The results improve understanding of the genetic mechanism underlying the variation in litter size of Erhualian pigs during the peri‐implantation period. 相似文献
854.
855.
856.
Xiang-Lan Sun Sarah J. Lessard Ding An Ho-Jin Koh Hiroyasu Esumi Michael F. Hirshman Laurie J. Goodyear 《Journal of cellular biochemistry》2019,120(1):685-696
The signaling mechanisms mediating myocardial glucose transport are not fully understood. Sucrose nonfermenting AMP-activated protein kinase (AMPK)-related kinase (SNARK) is an AMPK-related protein kinase that is expressed in the heart and has been implicated in contraction-stimulated glucose transport in mouse skeletal muscle. We first determined if SNARK is phosphorylated on Thr208, a site critical for SNARK activity. Mice were treated with exercise, ischemia, submaximal insulin, or maximal insulin. Treadmill exercise slightly, but significantly increased SNARK Thr208 phosphorylation. Ischemia also increased SNARK Thr208 phosphorylation, but there was no effect of submaximal or maximal insulin. HL1 cardiomyocytes were used to overexpress wild-type (WT) SNARK and to knockdown endogenous SNARK. Overexpression of WT SNARK had no effect on ischemia-stimulated glucose transport; however, SNARK knockdown significantly decreased ischemia-stimulated glucose transport. SNARK overexpression or knockdown did not alter insulin-stimulated glucose transport or glycogen concentrations. To study SNARK function in vivo, SNARK heterozygous knockout mice (SNARK+/−) and WT littermates performed treadmill exercise. Exercise-stimulated glucose transport was decreased by ~50% in hearts from SNARK+/− mice. In summary, exercise and ischemia increase SNARK Thr208 phosphorylation in the heart and SNARK regulates exercise-stimulated and ischemia-stimulated glucose transport. SNARK is a novel mediator of insulin-independent glucose transport in the heart. 相似文献
857.
Bolun Cheng Xiao Liang Yan Wen Ping Li Lu Zhang Mei Ma Shiqiang Cheng Yanan Du Li Liu Miao Ding Yan Zhao Feng Zhang 《Journal of cellular biochemistry》2019,120(9):14831-14837
858.
859.
860.