全文获取类型
收费全文 | 2313篇 |
免费 | 132篇 |
专业分类
2445篇 |
出版年
2022年 | 30篇 |
2021年 | 66篇 |
2020年 | 19篇 |
2019年 | 31篇 |
2018年 | 33篇 |
2017年 | 39篇 |
2016年 | 57篇 |
2015年 | 84篇 |
2014年 | 124篇 |
2013年 | 127篇 |
2012年 | 139篇 |
2011年 | 135篇 |
2010年 | 108篇 |
2009年 | 82篇 |
2008年 | 108篇 |
2007年 | 110篇 |
2006年 | 97篇 |
2005年 | 96篇 |
2004年 | 66篇 |
2003年 | 59篇 |
2002年 | 58篇 |
2001年 | 50篇 |
2000年 | 43篇 |
1999年 | 28篇 |
1997年 | 15篇 |
1996年 | 16篇 |
1993年 | 16篇 |
1992年 | 18篇 |
1991年 | 32篇 |
1990年 | 27篇 |
1989年 | 21篇 |
1988年 | 23篇 |
1987年 | 36篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 29篇 |
1983年 | 22篇 |
1982年 | 16篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 27篇 |
1977年 | 20篇 |
1976年 | 18篇 |
1975年 | 20篇 |
1973年 | 19篇 |
1972年 | 27篇 |
1971年 | 20篇 |
1970年 | 14篇 |
1969年 | 15篇 |
1967年 | 16篇 |
排序方式: 共有2445条查询结果,搜索用时 0 毫秒
81.
82.
83.
Sanket Kaushik Nagendra Singh Shavait Yamini Avinash Singh Mau Sinha Ashish Arora Punit Kaur Sujata Sharma Tej P. Singh 《PloS one》2013,8(7)
The incidences of infections caused by an aerobic Gram-negative bacterium, Acinetobacter baumannii are very common in hospital environments. It usually causes soft tissue infections including urinary tract infections and pneumonia. It is difficult to treat due to acquired resistance to available antibiotics is well known. In order to design specific inhibitors against one of the important enzymes, peptidyl-tRNA hydrolase from Acinetobacter baumannii, we have determined its three-dimensional structure. Peptidyl-tRNA hydrolase (AbPth) is involved in recycling of peptidyl-tRNAs which are produced in the cell as a result of premature termination of translation process. We have also determined the structures of two complexes of AbPth with cytidine and uridine. AbPth was cloned, expressed and crystallized in unbound and in two bound states with cytidine and uridine. The binding studies carried out using fluorescence spectroscopic and surface plasmon resonance techniques revealed that both cytidine and uridine bound to AbPth at nanomolar concentrations. The structure determinations of the complexes revealed that both ligands were located in the active site cleft of AbPth. The introduction of ligands to AbPth caused a significant widening of the entrance gate to the active site region and in the process of binding, it expelled several water molecules from the active site. As a result of interactions with protein atoms, the ligands caused conformational changes in several residues to attain the induced tight fittings. Such a binding capability of this protein makes it a versatile molecule for hydrolysis of peptidyl-tRNAs having variable peptide sequences. These are the first studies that revealed the mode of inhibitor binding in Peptidyl-tRNA hydrolases which will facilitate the structure based ligand design. 相似文献
84.
Susheel Kumar Raina Dhammaprakash Pandhari Wankhede Alok Krishna Sinha 《Plant signaling & behavior》2013,8(1)
Catharanthus roseus is an important source of pharmaceutically important Monoterpenoid Indole Alkaloids (MIAs). Accumulation of many of the MIAs is induced in response to abiotic stresses such as wound, ultra violet (UV) irradiations, etc. Recently, we have demonstrated a possible role of CrMPK3, a C. roseus mitogen-activated protein kinase in stress-induced accumulation of a few MIAs. Here, we extend our findings using Saccharomyces cerevisiae to investigate the role of CrMPK3 in giving tolerance to abiotic stresses. Yeast cells transformed with CrMPK3 was found to show enhanced tolerance to UV and heat stress. Comparison of CrMPK3 and SLT2, a MAPK from yeast shows high-sequence identity particularly at conserved domains. Additionally, heat stress is also shown to activate a 43 kDa MAP kinase, possibly CrMPK3 in C. roseus leaves. These findings indicate the role of CrMPK3 in stress-induced MIA accumulation as well as in stress tolerance. 相似文献
85.
Neha J. Pagidipati Mark D. Huffman Panniyammakal Jeemon Rajeev Gupta Prakash Negi Thannikot M. Jaison Satyavan Sharma Nakul Sinha Padinhare Mohanan B. G. Muralidhara Sasidharan Bijulal Sivasubramonian Sivasankaran Vijay K. Puri Jacob Jose K. Srinath Reddy Dorairaj Prabhakaran 《PloS one》2013,8(4)
Background
Studies from high-income countries have shown that women receive less aggressive diagnostics and treatment than men in acute coronary syndromes (ACS), though their short-term mortality does not appear to differ from men. Data on gender differences in ACS presentation, management, and outcomes are sparse in India.Methods and Results
The Detection and Management of Coronary Heart Disease (DEMAT) Registry collected data from 1,565 suspected ACS patients (334 women; 1,231 men) from ten tertiary care centers throughout India between 2007–2008. We evaluated gender differences in presentation, in-hospital and discharge management, and 30-day death and major adverse cardiovascular event (MACE; death, re-hospitalization, and cardiac arrest) rates. Women were less likely to present with STEMI than men (38% vs. 55%, p<0.001). Overall inpatient diagnostics and treatment patterns were similar between men and women after adjustment for potential confounders. Optimal discharge management with aspirin, clopidogrel, beta-blockers, and statin therapy was lower for women than men, (58% vs. 65%, p = 0.03), but these differences were attenuated after adjustment (OR = 0.86 (0.62, 1.19)). Neither the outcome of 30-day mortality (OR = 1.40 (0.62, 3.16)) nor MACE (OR = 1.00 (0.67, 1.48)) differed significantly between men and women after adjustment.Conclusions
ACS in-hospital management, discharge management, and 30-day outcomes did not significantly differ between genders in the DEMAT registry, though consistently higher treatment rates and lower event rates in men compared to women were seen. These findings underscore the importance of further investigation of gender differences in cardiovascular care in India. 相似文献86.
Kumar Alok Kalita J. Sinha Rohit A. Singh Gajendra B Anjum Shukla Mukti Tiwari Swasti Dhole T. N. Misra U. K. 《Neurochemical research》2020,45(9):2184-2195
Neurochemical Research - Role of autophagy in Japanese encephalitis viral (JEV) infection is not well known. In the present study, we reported the role of autophagy flux in microglia activation,... 相似文献
87.
88.
Molly Sharlach Douglas Dahlbeck Lily Liu Joshua Chiu José M. Jiménez-Gómez Seisuke Kimura Daniel Koenig Julin N. Maloof Neelima Sinha Gerald V. Minsavage Jeffrey B. Jones Robert E. Stall Brian J. Staskawicz 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(3):601-609
The RXopJ4 resistance locus from the wild accession Solanum pennellii (Sp) LA716 confers resistance to bacterial spot disease of tomato (S. lycopersicum, Sl) caused by Xanthomonas perforans (Xp). RXopJ4 resistance depends on recognition of the pathogen type III effector protein XopJ4. We used a collection of Sp introgression lines (ILs) to narrow the RXopJ4 locus to a 4.2-Mb segment on the long arm of chromosome 6, encompassed by the ILs 6-2 and 6-2-2. We then adapted or developed a collection of 14 molecular markers to map on a segregating F2 population from a cross between the susceptible parent Sl FL8000 and the resistant parent RXopJ4 8000 OC7. In the F2 population, a 190-kb segment between the markers J350 and J352 cosegregated with resistance. This fine mapping will enable both the identification of candidate genes and the detection of resistant plants using cosegregating markers. The RXopJ4 resistance gene(s), in combination with other recently characterized genes and a quantitative trait locus (QTL) for bacterial spot disease resistance, will likely be an effective tool for the development of durable resistance in cultivated tomato. 相似文献
89.
90.
Yongqi Deng Zhiwei Yang Gerald W. Shipps Sie-Mun Lo Robert West Joyce Hwa Shuqin Zheng Constance Farley Jean Lachowicz Margaret van Heek Alan S. Bass Dinesh P. Sinha Craig R. Mahon Mark E. Cartwright 《Bioorganic & medicinal chemistry letters》2013,23(3):791-796
Inhibitors based on a benzo-fused spirocyclic oxazepine scaffold were discovered for stearoyl-coenzyme A (CoA) desaturase 1 (SCD1) and subsequently optimized to potent compounds with favorable pharmacokinetic profiles and in vivo efficacy in reducing the desaturation index in a mouse model. Initial optimization revealed potency preferences for the oxazepine core and benzylic positions, while substituents on the piperidine portions were more tolerant and allowed for tuning of potency and PK properties. After preparation and testing of a range of functional groups on the piperidine nitrogen, three classes of analogs were identified with single digit nanomolar potency: glycine amides, heterocycle-linked amides, and thiazoles. Responding to concerns about target localization and potential mechanism-based side effects, an initial effort was also made to improve liver concentration in an available rat PK model. An advanced compound 17m with a 5-carboxy-2-thiazole substructure appended to the spirocyclic piperidine scaffold was developed which satisfied the in vitro and in vivo requirements for more detailed studies. 相似文献