全文获取类型
收费全文 | 25789篇 |
免费 | 1791篇 |
国内免费 | 2159篇 |
出版年
2024年 | 93篇 |
2023年 | 407篇 |
2022年 | 678篇 |
2021年 | 914篇 |
2020年 | 757篇 |
2019年 | 1157篇 |
2018年 | 992篇 |
2017年 | 649篇 |
2016年 | 695篇 |
2015年 | 913篇 |
2014年 | 1710篇 |
2013年 | 2007篇 |
2012年 | 1217篇 |
2011年 | 1689篇 |
2010年 | 1220篇 |
2009年 | 1281篇 |
2008年 | 1335篇 |
2007年 | 1445篇 |
2006年 | 1316篇 |
2005年 | 1157篇 |
2004年 | 981篇 |
2003年 | 817篇 |
2002年 | 817篇 |
2001年 | 485篇 |
2000年 | 445篇 |
1999年 | 402篇 |
1998年 | 440篇 |
1997年 | 331篇 |
1996年 | 339篇 |
1995年 | 334篇 |
1994年 | 271篇 |
1993年 | 248篇 |
1992年 | 241篇 |
1991年 | 223篇 |
1990年 | 163篇 |
1989年 | 147篇 |
1988年 | 128篇 |
1987年 | 124篇 |
1986年 | 80篇 |
1985年 | 131篇 |
1984年 | 195篇 |
1983年 | 156篇 |
1982年 | 173篇 |
1981年 | 95篇 |
1980年 | 79篇 |
1979年 | 79篇 |
1978年 | 53篇 |
1977年 | 30篇 |
1976年 | 26篇 |
1975年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Yunfan Sun Liang Wu Yu Zhong Kaiqian Zhou Yong Hou Zifei Wang Zefan Zhang Jiarui Xie Chunqing Wang Dandan Chen Yaling Huang Xiaochan Wei Yinghong Shi Zhikun Zhao Yuehua Li Ziwei Guo Qichao Yu Liqin Xu Jia Fan 《Cell》2021,184(2):404-421.e16
- Download : Download high-res image (233KB)
- Download : Download full-size image
12.
Selective increase in cytokeratin synthesis in cultured rat hepatocytes in response to hormonal stimulation 总被引:3,自引:0,他引:3
I Leroux-Nicollet M Noel H Baribault R Goyette N Marceau 《Biochemical and biophysical research communications》1983,114(2):556-563
Addition of a combination of insulin, dexamethasone and EGF at seeding time to cultured rat hepatocytes in serum-free medium caused a selective increase in the biosynthesis of particular cytokeratin components. This increase was prominent during the first day in culture. No significant increases were detected in the absence of hormones or in the presence of either hormones added alone or in pairs, except in the case of insulin plus dexamethasone, which yielded an effect close to that obtained with the three factors. Interestingly, the latter condition also maintained a high level of albumin production over a 6-day period in culture. 相似文献
13.
Shashank Hambarde Chi-Lin Tsai Raj K. Pandita Albino Bacolla Anirban Maitra Vijay Charaka Clayton R. Hunt Rakesh Kumar Oliver Limbo Remy Le Meur Walter J. Chazin Susan E. Tsutakawa Paul Russell Katharina Schlacher Tej K. Pandita John A. Tainer 《Molecular cell》2021,81(14):2989-3006.e9
- Download : Download high-res image (222KB)
- Download : Download full-size image
14.
Antonis E. Koromilas 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(3):644-649
Cells employ pro-survival and pro-adaptive pathways to cope with different forms of environmental stress. When stress is excessive, and the damage caused by it is unsustainable, cells engage pro-death pathways, which are in place to protect the host from the deleterious effects of harmed cells. Two important pathways that determine the balance between survival and death of stressed cells are the integrated stress response (ISR) and the mammalian target of rapamycin (mTOR), both of which converge at the level of mRNA translation. The two pathways have established avenues of communication to control their activity and determine the fate of stressed cells in a context-dependent manner. The functional interplay between the ISR and mTOR may have significant ramifications in the development and treatment of human diseases such as diabetes, neurodegeneration and cancer. 相似文献
15.
《Cell reports》2020,30(7):2065-2074.e4
- Download : Download high-res image (155KB)
- Download : Download full-size image
16.
17.
Ayenew Ejigou 《Biometrical journal. Biometrische Zeitschrift》1987,29(8):981-991
The odds ratio is known to closely approximate the relative risk when the disease is rare. Logistic regression models are often used to estimate such odds ratios, but here a different model is used which avoids the assumptions implicit in logistic modelling; it also has the advantage of providing a test of homogeneity for odds rat os in situations where the logistic model cannot. 相似文献
18.
The ECF™ lateral flow assay test is marketed to detect non-pregnancy in mares. The objectives of the present study were to determine the accuracy of the ECF test, the accuracy of the electronic reader accompanying the ECF test, and agreement between two human readers and the electronic reader. Serum samples were collected from anestrus, cycling but not inseminated, and inseminated mares, and were evaluated with the ECF™ test (EDP Biotech Company, Knoxville, TN, USA) at The Ohio State University and at the EDP Biotech Laboratory. Specificity ranged from 0.07 to 0.16, the negative predictive value ranged from 0.15 to 0.33, and accuracy ranged from 0.43 to 0.52. The electronic reader did not add improve the accuracy or predictive values of the test. Based on the electronic reader, 80.0% of the serum samples collected from the anestrus mares were false positives; Readers 1 and 2 had 60.0 and 33.3% false positives, respectively. For samples collected during the estrous cycle, 83.9% were false positives by the electronic reader, whereas Readers 1 and 2 had 43.7 and 26.4% false positives. We concluded that, regardless of whether the test strips were evaluated by a human or electronic reader, this assay was not accurate for determination of the non-pregnant mare. 相似文献
19.
Bone morphogenetic protein 2 (BMP-2) has been known for decades as a strong osteoinductive factor and for clinical applications is combined solely with collagen as carrier material. The growing concerns regarding side effects and the importance of BMP-2 in several developmental and physiological processes have raised the need to improve the design of materials by controlling BMP-2 presentation. Inspired by the natural cell environment, new material surfaces have been engineered and tailored to provide both physical and chemical cues that regulate BMP-2 activity. Here we describe surfaces designed to present BMP-2 to cells in a spatially and temporally controlled manner. This is achieved by trapping BMP-2 using physicochemical interactions, either covalently grafted or combined with other extracellular matrix components. In the near future, we anticipate that material science and biology will integrate and further develop tools for in vitro studies and potentially bring some of them toward in vivo applications. 相似文献
20.