全文获取类型
收费全文 | 11071篇 |
免费 | 889篇 |
国内免费 | 514篇 |
出版年
2023年 | 98篇 |
2022年 | 114篇 |
2021年 | 382篇 |
2020年 | 326篇 |
2019年 | 395篇 |
2018年 | 445篇 |
2017年 | 353篇 |
2016年 | 480篇 |
2015年 | 707篇 |
2014年 | 754篇 |
2013年 | 902篇 |
2012年 | 1066篇 |
2011年 | 930篇 |
2010年 | 546篇 |
2009年 | 507篇 |
2008年 | 592篇 |
2007年 | 519篇 |
2006年 | 442篇 |
2005年 | 386篇 |
2004年 | 355篇 |
2003年 | 294篇 |
2002年 | 253篇 |
2001年 | 199篇 |
2000年 | 186篇 |
1999年 | 168篇 |
1998年 | 82篇 |
1997年 | 96篇 |
1996年 | 88篇 |
1995年 | 76篇 |
1994年 | 72篇 |
1993年 | 69篇 |
1992年 | 87篇 |
1991年 | 85篇 |
1990年 | 63篇 |
1989年 | 48篇 |
1988年 | 44篇 |
1987年 | 47篇 |
1986年 | 35篇 |
1985年 | 37篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 15篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1972年 | 12篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Chiao-Fang Teng Wen-Chuan Hsieh Han-Chieh Wu Yih-Jyh Lin Hung-Wen Tsai Wenya Huang Ih-Jen Su 《PloS one》2015,10(4)
Hepatitis B virus (HBV) pre-S2 mutant can induce hepatocellular carcinoma (HCC) via the induction of endoplasmic reticulum stress to activate mammalian target of rapamycin (MTOR) signaling. The association of metabolic syndrome with HBV-related HCC raises the possibility that pre-S2 mutant-induced MTOR activation may drive the development of metabolic disorders to promote tumorigenesis in chronic HBV infection. To address this issue, glucose metabolism and gene expression profiles were analyzed in transgenic mice livers harboring pre-S2 mutant and in an in vitro culture system. The pre-S2 mutant transgenic HCCs showed glycogen depletion. The pre-S2 mutant initiated an MTOR-dependent glycolytic pathway, involving the eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1), Yin Yang 1 (YY1), and myelocytomatosis oncogene (MYC) to activate the solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1), contributing to aberrant glucose uptake and lactate production at the advanced stage of pre-S2 mutant transgenic tumorigenesis. Such a glycolysis-associated MTOR signal cascade was validated in human HBV-related HCC tissues and shown to mediate the inhibitory effect of a model of combined resveratrol and silymarin product on tumor growth. Our results provide the mechanism of pre-S2 mutant-induced MTOR activation in the metabolic switch in HBV tumorigenesis. Chemoprevention can be designed along this line to prevent HCC development in high-risk HBV carriers. 相似文献
2.
3.
4.
Dispersive liquid–liquid microextraction (DLLME) coupled with ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) was developed for the extraction and determination of 10 β2-agonists in animal urine. Some experimental parameters, such as the type and volume of the extraction solvent, the concentration of the dispersant, the salt concentration, the pH value of the sample solution, the extraction time and the speed of centrifugation, were investigated and optimized. Under the optimized conditions, a good enrichment factors (4.8 to 32.3) were obtained for the extraction. The enrichment factor show that the concentration rate of DLLME is significantly higher than other pretreatment methods, and the detection sensitivity has been greatly improved. The calibration curves were linear, the correlation coefficient ranged from 0.9928 to 0.9999 for the concentration range of 0.05 to 50 ngmL-1 and 0.1 to 50 ngmL-1, and the relative standard deviations (RSDs, n = 15, intra and inter-day precision) at a concentration of 5 ngmL-1 were in the range of 1.8 to 14.6%. The limits of detection (LODs) for the 10 β2-agonists, based on a signal-to-noise ratio (S/N) of 3, were in the range of 0.01 to 0.03 ngmL-1. The proposed method was used to identify β2-agonists in three types of animal urine (swine, cattle, sheep), and the relative recoveries from each matrix were in the range of 89.2 to 106.8%, 90.0 to 109.8% and 89.2 to 107.2%, respectively. 相似文献
5.
6.
Su Hao Lo Ellen Weisberg Lan Bo Chen 《BioEssays : news and reviews in molecular, cellular and developmental biology》1994,16(11):817-823
Cytoskeletal proteins provide the structural foundation that allows cells to exist in a highly organized manner. Recent evidence suggests that certain cytoskeletal proteins not only maintain structural integrity, but might also be associated with signal transduction and suppression of tumorigenesis. Since the time of the discovery of tensin, a fair amount of data has been gathered which supports the notion that tensin is one such protein possessing these characteristics. In this review, we discuss recent studies that: (1) elucidate a role for tensin in maintenance of cellular structure and signal transduction; (2) implicate tensin as the anchor for actin filaments at the focal adhesion; (3) describe the phosphorylation of tensin; (4) describe potential targets for its Src homology region 2 domain; (5) describe the association between tensin and the nuclear protein p130; and (6) demonstrate that increased tensin expression in a cell line appears to reduce its transformation potential. 相似文献
7.
8.
9.
10.