全文获取类型
收费全文 | 4838篇 |
免费 | 550篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 165篇 |
妇产科学 | 95篇 |
基础医学 | 493篇 |
口腔科学 | 55篇 |
临床医学 | 701篇 |
内科学 | 683篇 |
皮肤病学 | 106篇 |
神经病学 | 556篇 |
特种医学 | 101篇 |
外科学 | 456篇 |
综合类 | 57篇 |
一般理论 | 7篇 |
预防医学 | 611篇 |
眼科学 | 39篇 |
药学 | 362篇 |
中国医学 | 3篇 |
肿瘤学 | 851篇 |
出版年
2024年 | 4篇 |
2023年 | 38篇 |
2022年 | 58篇 |
2021年 | 138篇 |
2020年 | 92篇 |
2019年 | 130篇 |
2018年 | 193篇 |
2017年 | 151篇 |
2016年 | 160篇 |
2015年 | 192篇 |
2014年 | 261篇 |
2013年 | 334篇 |
2012年 | 467篇 |
2011年 | 482篇 |
2010年 | 238篇 |
2009年 | 236篇 |
2008年 | 285篇 |
2007年 | 292篇 |
2006年 | 298篇 |
2005年 | 253篇 |
2004年 | 262篇 |
2003年 | 195篇 |
2002年 | 165篇 |
2001年 | 35篇 |
2000年 | 40篇 |
1999年 | 52篇 |
1998年 | 42篇 |
1997年 | 35篇 |
1996年 | 12篇 |
1995年 | 30篇 |
1994年 | 9篇 |
1993年 | 18篇 |
1992年 | 23篇 |
1991年 | 28篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 5篇 |
1977年 | 6篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1967年 | 3篇 |
排序方式: 共有5399条查询结果,搜索用时 15 毫秒
31.
32.
Staphylococcus aureus aconitase inactivation unexpectedly inhibits post-exponential-phase growth and enhances stationary-phase survival
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Somerville GA Chaussee MS Morgan CI Fitzgerald JR Dorward DW Reitzer LJ Musser JM 《Infection and immunity》2002,70(11):6373-6382
Staphylococcus aureus preferentially catabolizes glucose, generating pyruvate, which is subsequently oxidized to acetate under aerobic growth conditions. Catabolite repression of the tricarboxylic acid (TCA) cycle results in the accumulation of acetate. TCA cycle derepression coincides with exit from the exponential growth phase, the onset of acetate catabolism, and the maximal expression of secreted virulence factors. These data suggest that carbon and energy for post-exponential-phase growth and virulence factor production are derived from the catabolism of acetate mediated by the TCA cycle. To test this hypothesis, the aconitase gene was genetically inactivated in a human isolate of S. aureus, and the effects on physiology, morphology, virulence factor production, virulence for mice, and stationary-phase survival were examined. TCA cycle inactivation prevented the post-exponential growth phase catabolism of acetate, resulting in premature entry into the stationary phase. This phenotype was accompanied by a significant reduction in the production of several virulence factors and alteration in host-pathogen interaction. Unexpectedly, aconitase inactivation enhanced stationary-phase survival relative to the wild-type strain. Aconitase is an iron-sulfur cluster-containing enzyme that is highly susceptible to oxidative inactivation. We speculate that reversible loss of the iron-sulfur cluster in wild-type organisms is a survival strategy used to circumvent oxidative stress induced during host-pathogen interactions. Taken together, these data demonstrate the importance of the TCA cycle in the life cycle of this medically important pathogen. 相似文献
33.
34.
Lynch HT Deters CA Snyder CL Lynch JF Villeneuve P Silberstein J Martin H Narod SA Brand RE 《Cancer Genetics and Cytogenetics》2005,158(2):119-125
Anecdotal reports and series studies indicate that 5-10% of pancreatic cancer (PC) cases are familial. In addition, PC is associated with a variety of hereditary cancer syndromes. PC appears to be an integral cancer in the hereditary breast-ovarian cancer (HBOC) syndrome, with most notice given to the role of BRCA2. Our purpose is to call attention to BRCA1, which also predisposes to PC. Using data from our familial breast cancer registry, we identified 19 BRCA1/2 families that contain PC affecteds in the pedigrees, 15 with BRCA1 mutations and 4 with BRCA2 mutations. The association between BRCA2 and pancreatic cancer is well established; however, a definite link with pancreatic cancer in families carrying a BRCA1 mutation has been far less studied. Thus, the focus of this report is on 9 of the 15 BRCA1 families, in which PC affecteds were either confirmed carriers of the BRCA1 mutation or were inferred as probable obligate BRCA1 mutation carriers. The numbers are small, but nevertheless illustrate the finding of others of an apparent association between PC and BRCA1-mutation-bearing families. Given the dismal prognosis of PC, with the only current hope for survival being through surgical extirpation of the pancreas prior to metastasis, it is prudent that we realize the potential predisposition toward PC via BRCA1, in the hope of early diagnosis and prevention. 相似文献
35.
Ana L Sanchez Carrie M Langdon Mahmood Akhtar Jun Lu Carl D Richards Premysl Bercik Derek M McKay 《Journal of interferon & cytokine research》2003,23(4):193-201
The use of biologics has promising potential in the treatment of inflammation. Studies with cultured cells and mouse models of disease have ascribed proinflammatory and anti-inflammatory functions to oncostatin M (OSM) and the related cytokine, interleukin-6 (IL-6). Here, we examined the effect of systemic administration of adenoviral (Ad) vectors encoding either murine OSM (AdMuOSM) or murine IL-6 (AdMuIL-6) in a mouse model of colitis. BALB/c mice were treated with a 5-day course of 4% dextran-sodium sulfate (DSS) water with or without administration of adenoviral vectors (i.p. or i.m. at 10(7) plaque-forming units [pfu]) given as a cotreatment or therapy. The deletion variant of the adenovirus served as a control for adenoviral infection. Colitis was assessed by (1) morphology (damage score, macrophage infiltration, apoptosis) and (2) function (myeloperoxidase activity and Ussing chamber analysis of epithelial ion transport). Infection with adenovirus alone did not affect colonic form or function. AdMuOSM (either i.p. or i.m.) significantly reduced the severity of the DSS-induced colitis. There was less damage, reduced macrophage infiltration, fewer apoptotic bodies, and a significant improvement in stimulated ion transport in colonic tissues from the treated mice. No benefit of AdMuIL-6 treatment was observed in this model system. Thus, systemic administration of AdMuOSM given as a cotreatment and to a lesser extent as a therapy was found to be of benefit in DSS-induced colitis, a murine model of inflammatory bowel disease (IBD). 相似文献
36.
Heike CL Cunningham ML Steiner RD Wenkert D Hornung RL Gruss JS Gannon FH McAlister WH Mumm S Whyte MP 《American journal of medical genetics. Part A》2005,(2):67-77
Epidermal nevus syndrome (ENS) is a rare, sporadic, congenital disorder of unknown etiology featuring a complex and highly variable phenotype that can include focal or generalized skeletal disease. We describe a young man with ENS manifesting right-sided linear skin lesions, generalized weakness, diffuse osteopenia associated with hypophosphatemic rickets, and distinctive focal bone lesions ipsilateral to the skin findings. Review of the literature concerning ENS-associated skeletal disease suggested such focal bone defects are fibrous dysplasia, but our patient did not have the typical radiographic or histopathologic findings of fibrous dysplasia. Nevertheless, his circulating fibroblast growth factor 23 (FGF-23) level was elevated, likely functioning as a "phosphatonin," yet no activating mutations in GNAS previously reported in fibrous dysplasia or McCune-Albright syndrome were detected in his leukocytes or affected skin. We postulate that the focal skeletal disease, although different than fibrous dysplasia, may be a source of FGF-23 in ENS. 相似文献
37.
38.
39.
Almanza Jennifer I. Karbeah J.Mag Tessier Katelyn M. Neerland Carrie Stoll Kathrin Hardeman Rachel R. Vedam Saraswathi 《Maternal and child health journal》2022,26(4):895-904
Maternal and Child Health Journal - National studies report that birth center care is associated with reduced racial and ethnic disparities and reduced experiences of mistreatment. In the US, there... 相似文献
40.
Asher Y. Rosinger Samantha M. Olson Sascha R. Ellington Janice Perez-Padilla Regina M. Simeone Caitlin S. Pedati Betsy A. Schroeder Gilberto A. Santiago Freddy A. Medina Jorge L. Muoz-Jordn Laura E. Adams Romeo R. Galang Miguel Valencia-Prado Sonia Bakkour Candimar Coln Mary Goodwin Dana Meaney-Delman Jennifer S. Read Lyle R. Petersen Denise J. Jamieson Carmen C. Deseda Margaret A. Honein Brenda Rivera-García Carrie K. Shapiro-Mendoza 《Emerging infectious diseases》2021,27(5):1505
We evaluated nucleic acid amplification testing (NAAT) for Zika virus on whole-blood specimens compared with NAAT on serum and urine specimens among asymptomatic pregnant women during the 2015–2016 Puerto Rico Zika outbreak. Using NAAT, more infections were detected in serum and urine than in whole blood specimens. 相似文献