全文获取类型
收费全文 | 2401篇 |
免费 | 115篇 |
国内免费 | 1篇 |
出版年
2023年 | 11篇 |
2022年 | 17篇 |
2021年 | 45篇 |
2020年 | 28篇 |
2019年 | 33篇 |
2018年 | 40篇 |
2017年 | 30篇 |
2016年 | 53篇 |
2015年 | 92篇 |
2014年 | 110篇 |
2013年 | 171篇 |
2012年 | 144篇 |
2011年 | 176篇 |
2010年 | 88篇 |
2009年 | 104篇 |
2008年 | 149篇 |
2007年 | 154篇 |
2006年 | 154篇 |
2005年 | 155篇 |
2004年 | 175篇 |
2003年 | 148篇 |
2002年 | 134篇 |
2001年 | 18篇 |
2000年 | 10篇 |
1999年 | 24篇 |
1998年 | 34篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 20篇 |
1992年 | 13篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 12篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1973年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有2517条查询结果,搜索用时 15 毫秒
991.
Shingo Tamura Toshinori Bito Masamitsu Ichihashi Masato Ueda 《Pigment cell & melanoma research》2003,16(5):470-476
Genistein, a naturally occurring isoflavone found chiefly in soybeans, has been reported to be a potent antitumor agent. Genistein is presumed to exert multiple effects related to the inhibition of cancer growth. Metastatic melanoma is a chemotherapy‐refractory neoplasm. The present study was designed to explore the possible activity of genistein to inhibit the aberrant proliferation and to induce apoptosis of human malignant melanoma cells in cooperation with cisplatin treatment. Five human melanoma cell lines were utilized for these experiments. Genistein at physiologic concentrations (20 μM) did not induce apoptosis by itself but did enhance cisplatin‐induced apoptosis in all five human melanoma cell lines tested. The enhanced susceptibility among the cell lines was diverse. Changes in the expression of two anti‐apoptotic proteins, bcl‐2 and bcl‐xL, and one pro‐apoptotic protein, apoptotic protease activating factor‐1 (Apaf‐1), were examined. Genistein alone or cisplatin alone generally did not alter bcl‐2 expression or bcl‐xL expression, but slightly increased Apaf‐1 in some cell lines. The combined treatment with genistein and cisplatin significantly reduced bcl‐2 and bcl‐xL protein and increased Apaf‐1 protein expression. These data suggest that genistein therapy may enhance the chemosensitivity of melanoma patients. 相似文献
992.
993.
Chun-Hong Qiu Masato Ohe Noriyuki Koibuchi Shigeru Matsuzaki 《The journal of histochemistry and cytochemistry》2004,52(2):187-192
Apoptosis in the testis and prostate exposed to disrupters of endocrine function, including diethylstilbestrol (DES), during neonatal or postnatal periods has repeatedly been demonstrated, but not in the mature epididymis. We investigated the effects of DES, a potent and synthetic estrogen, on apoptosis in the adult. Adult male golden hamsters received an SC injection of DES and were then sacrificed to collect epididymides after 1, 4, or 7 days of treatment. A significant decrease in epididymal weight and an increase in apoptotic cells were shown on the first day after DES injection. Flow cytometry showed that DES treatment (1 mg/kg) for 1, 4, or 7 days induced significant apoptosis both in the caput and the cauda epididymides. Greater numbers of apoptotic cells were detected in the caput than in the cauda at a fixed time after DES treatment. Serum levels of testosterone decreased markedly within 24 hr after DES administration, reaching undetectable levels of 0.1 ng/ml at 4 days and thereafter. These results indicate that DES administration can increase epididymal apoptosis with a decrease in serum testosterone levels. Because DES used to be injected into domestic animals, adult males also have a chance to take this substance through food. Our study indicates that exposure to DES in adults is as toxic as that in the perinatal period. 相似文献
994.
There is a region exhibiting a similarity of amino acid sequence near the carboxyl-terminal segment of each FAD-containing
oxidoreductase. In this region, four amino acid residues—Thr, Ala, Gly, and Asp—are highly conserved. To determine the involvement
of the four amino acid residues (Thr-469, Ala-476, Gly-478, and Asp-479) in the activity of NADH dehydrogenase of an alkaliphilic
Bacillus, mutations of these amino acid residues were conducted. In spite of high conservation, mutations of Thr-469 and Ala-476 to
Ala and Ser, respectively, did not lead to a critical loss of enzyme activity. However, mutations of Gly-478 and Asp-479 to
Ala caused a complete loss of the activity, which appears to result from the loss of binding capacity of FAD.
Received: 3 July 2002 / Accepted: 29 July 2002 相似文献
995.
Umbelopsis gibberispora is described as a new species in the genus Umbelopsis, Umbelopsidaceae, Mucorales. The species differs from others in this genus by ellipsoidal sporangiospores with unilaterally
thickened walls. Phylogenetic analyses based on nuclear large subunit ribosomal DNA (nLSU rDNA) partial sequences suggest
that U. gibberispora, U. swartii, and U. westeae form a clade together with the strains of Umbelopsis ramanniana. The ex-type strain of Micromucor ramannianus var. angulisporus is found to be very close to Umbelopsis vinacea, whereas other isolates identified under the former name in the sense of Linnemann fall in the U. ramanniana subclade. For these isolates, a new species, Umbelopsis angularis, is introduced. Phylogenetic relationships among Umbelopsis species are discussed related to their attributes of the sporangial wall and mature spore shapes.
Received: August 27, 2002 / Accepted: March 11, 2003
Acknowledgments We thank Dr. Takashi Ohsono, Graduate School of Agriculture, Kyoto University, Japan, for providing the strain of U. gibberispora (CBS 109328). We also thank Dr. Wieland Meyer, University of Sydney, Australia for access to the phylogenetic tree based
on ITS sequence data before publishing, and Dr. Richard C. Summerbell, Centraalbureau von Schimmelcultures, the Netherlands,
for linguistic corrections. 相似文献
996.
997.
998.
Sera Toshihiro Kobayashi Hiroaki Hoshino Masato Uesugi Kentaro Matsumoto Takeshi Tanaka Masao 《Biomechanics and modeling in mechanobiology》2019,18(2):375-385
Biomechanics and Modeling in Mechanobiology - In this study, based on the measurements of intracortical vascular canal structure, we investigated the disuse effect on local O2 supply in the... 相似文献
999.
1000.
采用蔗糖密度离心方法分离完整叶绿体,进一步分离叶绿体被膜,借助SDS-PAGE分析了2种油菜叶绿体被膜的蛋白组分.用对拟南芥叶绿体外被膜上存在Toc33的特异抗体,检测到油菜叶绿体被膜上存在Toc33转运蛋白.Toc33在2种油菜中的相对含量不同,黄化油菜叶绿体被膜中高于野生油菜叶绿体被膜. 相似文献