全文获取类型
收费全文 | 1835058篇 |
免费 | 133284篇 |
国内免费 | 2781篇 |
专业分类
耳鼻咽喉 | 24128篇 |
儿科学 | 60422篇 |
妇产科学 | 49402篇 |
基础医学 | 276142篇 |
口腔科学 | 51621篇 |
临床医学 | 169086篇 |
内科学 | 354040篇 |
皮肤病学 | 40615篇 |
神经病学 | 141706篇 |
特种医学 | 67868篇 |
外国民族医学 | 335篇 |
外科学 | 264248篇 |
综合类 | 38491篇 |
现状与发展 | 4篇 |
一般理论 | 692篇 |
预防医学 | 146624篇 |
眼科学 | 41830篇 |
药学 | 136694篇 |
9篇 | |
中国医学 | 4150篇 |
肿瘤学 | 103016篇 |
出版年
2018年 | 19683篇 |
2017年 | 15106篇 |
2016年 | 16587篇 |
2015年 | 19028篇 |
2014年 | 26152篇 |
2013年 | 39880篇 |
2012年 | 53657篇 |
2011年 | 56977篇 |
2010年 | 33213篇 |
2009年 | 31789篇 |
2008年 | 53651篇 |
2007年 | 57458篇 |
2006年 | 57452篇 |
2005年 | 55443篇 |
2004年 | 53547篇 |
2003年 | 51171篇 |
2002年 | 49593篇 |
2001年 | 84556篇 |
2000年 | 86174篇 |
1999年 | 72166篇 |
1998年 | 19869篇 |
1997年 | 17612篇 |
1996年 | 18171篇 |
1995年 | 17266篇 |
1994年 | 16045篇 |
1993年 | 14940篇 |
1992年 | 56697篇 |
1991年 | 56088篇 |
1990年 | 54346篇 |
1989年 | 53120篇 |
1988年 | 49009篇 |
1987年 | 47838篇 |
1986年 | 45619篇 |
1985年 | 42955篇 |
1984年 | 32468篇 |
1983年 | 28029篇 |
1982年 | 16217篇 |
1981年 | 14651篇 |
1979年 | 30409篇 |
1978年 | 22026篇 |
1977年 | 18476篇 |
1976年 | 17400篇 |
1975年 | 18885篇 |
1974年 | 22617篇 |
1973年 | 22193篇 |
1972年 | 20886篇 |
1971年 | 19584篇 |
1970年 | 18620篇 |
1969年 | 17414篇 |
1968年 | 16158篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Aging alters bladder functions where a decrease in filling, storage and emptying is observed. These changes cause urinary incontinence, especially in women. The aim of this study is to examine how aging affects the intracellular calcium movements due to agonist-induced contractions in permeabilized female rat bladder. Urinary bladder isolated from young and old female Sprague-Dawley rats were used. Small detrusor strips were permeabilized with β-escin. The contractile responses induced with agonists were compared between young and old groups. Carbachol-induced contractions were decreased in permeabilized detrusor from old rats compared to young group. Heparin and ryanodine decreased carbachol-induced contractions in young rats where only heparin inhibited these contractions in olds. Caffeine-induced contractions but not inositol triphosphate (IP3)-induced contractions were decreased in old group compared to youngs. The cumulative calcium response curves (pCa 8–4) were also decreased in old rats. Carbachol-induced calcium sensitization responses did not alter by age where GTP-β-S and GF-109203X but not Y-27632 inhibited these responses. Carbachol-induced contractions decrease with aging in rat bladder detrusor. It can be postulated as IP3-induced calcium release (IICR) is primarily responsible for the contractions in older rats where the decrease in carbachol contractions in aging may be as a result of a decrease in calcium-induced calcium release (CICR), rather than carbachol-induced calcium sensitization. 相似文献
32.
E. Likotrafiti K. M. Tuohy G. R. Gibson R. A. Rastall 《International journal of food sciences and nutrition》2016,67(2):83-91
The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited. 相似文献
33.
34.
N. S. Hari Narayana Moorthy Sergio F. Sousa Maria J. Ramos Pedro A. Fernandes 《Medicinal chemistry research》2016,25(7):1340-1357
Farnesyltransferase (FTase) is one of the prenyltransferase family enzymes that catalyse the transfer of 15-membered isoprenoid (farnesyl) moiety to the cysteine of CAAX motif-containing proteins including Rho and Ras family of G proteins. Inhibitors of FTase act as drugs for cancer, malaria, progeria and other diseases. In the present investigation, we have developed two structure-based pharmacophore models from protein–ligand complex (3E33 and 3E37) obtained from the protein data bank. Molecular dynamics (MD) simulations were performed on the complexes, and different conformers of the same complex were generated. These conformers were undergone protein–ligand interaction fingerprint (PLIF) analysis, and the fingerprint bits have been used for structure-based pharmacophore model development. The PLIF results showed that Lys164, Tyr166, TrpB106 and TyrB361 are the major interacting residues in both the complexes. The RMSD and RMSF analyses on the MD-simulated systems showed that the absence of FPP in the complex 3E37 has significant effect in the conformational changes of the ligands. During this conformational change, some interactions between the protein and the ligands are lost, but regained after some simulations (after 2 ns). The structure-based pharmacophore models showed that the hydrophobic and acceptor contours are predominantly present in the models. The pharmacophore models were validated using reference compounds, which significantly identified as HITs with smaller RMSD values. The developed structure-based pharmacophore models are significant, and the methodology used in this study is novel from the existing methods (the original X-ray crystallographic coordination of the ligands is used for the model building). In our study, along with the original coordination of the ligand, different conformers of the same complex (protein–ligand) are used. It concluded that the developed methodology is significant for the virtual screening of novel molecules on different targets. 相似文献
35.
Stelter K. Theodoraki M. N. Becker S. Tsekmistrenko V. Olzowy B. Ledderose G. 《European archives of oto-rhino-laryngology》2015,272(3):639-639
European Archives of Oto-Rhino-Laryngology - 相似文献
36.
37.
38.
Michael E Egger Joanna M Ohlendorf Charles R Scoggins Kelly M McMasters Robert C G Martin II 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2015,17(9):839-845
BackgroundThe aim of this paper is to assess the current state of quality and outcomes measures being reported for hepatic resections in the recent literature.MethodsMedline and PubMed databases were searched for English language articles published between 1 January 2002 and 30 April 2013. Two examiners reviewed each article and relevant citations for appropriateness of inclusion, which excluded papers of liver donor hepatic resections, repeat hepatectomies or meta-analyses. Data were extracted and summarized by two examiners for analysis.ResultsFifty-five studies were identified with suitable reporting to assess peri-operative mortality in hepatic resections. In only 35% (19/55) of the studies was the follow-up time explicitly stated, and in 47% (26/55) of studies peri-operative mortality was limited to in-hospital or 30 days. The time period in which complications were captured was not explicitly stated in 19 out of 28 studies. The remaining studies only captured complications within 30 days of the index operation (8/28). There was a paucity of quality literature addressing truly patient-centred outcomes.ConclusionQuality outcomes after a hepatic resection are inconsistently reported in the literature. Quality outcome studies for a hepatectomy should report mortality and morbidity at a minimum of 90 days after surgery. 相似文献
39.
40.
Michael L. Goodman Miriam S. Mutambudzi Stanley Gitari Philip H. Keiser Sarah E. Seidel 《Vulnerable children and youth studies》2016,11(4):366-378
There are an estimated 56 million orphans and vulnerable children across sub-Saharan Africa. Communities typically care for orphan children through informal caring arrangements – either within or outside of kinship networks. Within Kenya, an estimated 250,000 children live on the streets. There is less research related to fostering attitudes of this special population than orphans and vulnerable children generally. Important research over the past decade has illuminated multiple ways in which children are made more vulnerable because of HIV, including parental death and street-migration from HIV-affected households. As HIV transitions from a terminal illness to a chronic, manageable one, research is also required to establish how parents living with HIV can be an asset to children. In this study, we assess whether mothers living with HIV were very willing to foster biologically-related children, and street-involved children, how these fostering attitudes differed from mothers not living with HIV, and whether differences in fostering attitudes by reported HIV status were mediated by social support, family functioning and general self-rated health. Approximately 40% of mothers living with HIV were very willing to provide long-term foster care to biologically-related or street-involved children. This was less than the percentage of mothers not living with HIV, who were very willing to foster biologically-related children (61%) or street-involved children (58%). Significant portions of these differences were explained by social support, family functioning and general self-rated health. Multi-sectoral approaches are suggested by these findings in order to improve the child-fostering capacity of mothers living with HIV. Improving social support, family functioning and general self-rated health among HIV-infected mothers may not only provide protective benefits for the mothers and their children, but also expand the community’s capacity to care for orphan and vulnerable children. 相似文献