全文获取类型
收费全文 | 25369篇 |
免费 | 1814篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 1036篇 |
妇产科学 | 859篇 |
基础医学 | 2922篇 |
口腔科学 | 312篇 |
临床医学 | 4140篇 |
内科学 | 4779篇 |
皮肤病学 | 445篇 |
神经病学 | 2366篇 |
特种医学 | 384篇 |
外科学 | 2040篇 |
综合类 | 347篇 |
一般理论 | 28篇 |
预防医学 | 3742篇 |
眼科学 | 365篇 |
药学 | 1570篇 |
中国医学 | 34篇 |
肿瘤学 | 1745篇 |
出版年
2023年 | 181篇 |
2022年 | 234篇 |
2021年 | 403篇 |
2020年 | 346篇 |
2019年 | 555篇 |
2018年 | 634篇 |
2017年 | 513篇 |
2016年 | 552篇 |
2015年 | 614篇 |
2014年 | 838篇 |
2013年 | 1334篇 |
2012年 | 1964篇 |
2011年 | 1929篇 |
2010年 | 1087篇 |
2009年 | 1024篇 |
2008年 | 1656篇 |
2007年 | 1820篇 |
2006年 | 1698篇 |
2005年 | 1753篇 |
2004年 | 1662篇 |
2003年 | 1505篇 |
2002年 | 1451篇 |
2001年 | 228篇 |
2000年 | 181篇 |
1999年 | 205篇 |
1998年 | 294篇 |
1997年 | 216篇 |
1996年 | 192篇 |
1995年 | 200篇 |
1994年 | 173篇 |
1993年 | 150篇 |
1992年 | 112篇 |
1991年 | 99篇 |
1990年 | 110篇 |
1989年 | 98篇 |
1988年 | 75篇 |
1987年 | 73篇 |
1986年 | 74篇 |
1985年 | 89篇 |
1984年 | 99篇 |
1983年 | 71篇 |
1982年 | 92篇 |
1981年 | 77篇 |
1980年 | 71篇 |
1979年 | 50篇 |
1978年 | 55篇 |
1977年 | 41篇 |
1975年 | 35篇 |
1973年 | 24篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Jane A. Kent-Braun PhD Khema R. Sharma MD Michael W. Weiner MD Robert G. Miller MD 《Muscle & nerve》1994,17(10):1162-1169
We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise. MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 ± 0.22 in controls but to only 0.66 ± 0.04 in MS (P < 0.01); likewise, pH was 6.75±0.04 in controls and unchanged (7.06 ± 0.04) in MS (P <0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophsyiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane(excitation–contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS. © 1994 John Wiley & Sons, Inc. 相似文献
62.
63.
64.
Jane Naish 《Sociology of health & illness》1994,16(5):696-698
65.
66.
Jeffrey F. Waring Rita Ciurlionis Robert A. Jolly Matthew Heindel Gerry Gagne Jane A. Fagerland Roger G. Ulrich 《Toxicology in vitro》2003,17(5-6):693-701
In vitro human hepatocyte cultures are a key tool in the investigation of xenobiotic toxicity and metabolism. In most in vitro hepatocyte studies, the cells are allowed to adhere to an extracellular matrix, such as collagen. Unfortunately, the ability of freshly isolated hepatocytes to adhere to collagen varies from donor to donor. We used microarray analysis to determine what gene expression differences exist between hepatocytes in suspension and hepatocytes attached to collagen. Results from different donors showed a considerable difference in gene expression patterns between the two hepatocyte populations. In addition, we also compared the gene expression profiles of hepatocytes in culture with liver tissue. The results showed that both hepatocytes in suspension and hepatocytes attached to collagen display significant gene expression differences compared with liver tissue. Finally, we show that both populations of hepatocytes are responsive to dexamethasone and regulate some of the same genes. Overall, our results suggest that either significant gene expression changes occur in isolated hepatocytes or that suspended and attached cells represent different populations of hepatocytes found in intact livers. 相似文献
67.
Lichun Zhong Eugenia Chu Jane Chu Teh-Ching Chu 《Journal of ocular pharmacology and therapeutics》2003,19(5):425-436
It has been demonstrated that natriuretic peptides lower intraocular pressure, however, the underlying cellular mechanism(s) mediating this response remain(s) to be determined. The purpose of this study was to investigate the effects of C-type natriuretic peptide (CNP) on pH(i), cGMP/cAMP and expression of atrial natriuretic peptide receptor (NPR-A), brain natriuretic peptide receptor (NPR-B) and C-type natriuretic peptide receptor (NPR-C), in HTM cells. At concentrations of 10(-7) M, CNP caused an acidification of pH(i). In addition, CNP caused a dose-dependent increase in cGMP formation and inhibition of forskolin-stimulated cAMP accumulation. These changes were not significantly altered in the absence of 10(-3) M isobutylmethylxanthine (IBMX). Treatment with the NPR-A antagonist, anantin, produced no influence on basal cGMP/cAMP levels, the CNP-stimulated cGMP accumulation and CNP-induced inhibition of forskolin-stimulated cAMP accumulation. However, CNP-induced reduction of forskolin-stimulated cAMP accumulation was inhibited by pretreatment with pertussis toxin (PTX). Furthermore, NPRB receptors were predominantly expressed and pretreatment with CNP (10(-7) M, 24hr) enhanced all NPR mRNAs expression which was not altered by higher concentrations or longer incubation. Results demonstrate that NPR-A, NPR-B and NPR-C receptors' expression can be up-regulated by CNP treatment. CNP activates NPR-B receptors preferentially to increase cGMP accumulation and acts through the PTX-sensitive cAMP-signaling pathway leading to a decrease in pH(i). 相似文献
68.
Elizabeth Jane Bragg RNC MSN 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1997,26(5):577-584
Adolescence is the most formative time in the lives of women. During this time girls are making choices that have implications for the rest of their lives. Adolescence also can be a time when the negative impact of sexual and physical abuse from childhood begins to take its toll, contributing to adolescent pregnancy and substance abuse. In the last decade the incidences of pregnancy and drug use in the adolescent population have increased, with 80% of teenagers reported being sexually active by the age of 19 years and 80% of high school seniors reporting use of alcohol; 64% reporting smoking; and 41 % reporting marijuana use in 1995. Nurses working with pregnant adolescents must screen for substance abuse problems and physical abuse. If problems are identified, the nurse should refer the adolescent for counseling. 相似文献
69.
70.
Jane Farmer Patrick Dawson Elizabeth Martin Janet Tucker 《Health services management research》2007,20(1):59-68
There is a wealth of material on 'how to do' change plus empirical work revealing change process complexity. In health care, the relevance of context is highlighted, but studies of rural health-care change have focused on community impacts. There is little to inform health-care managers of how remoteness and rurality impact upon change processes. This study considered Scottish maternity units and aimed to identify issues in the change process associated with rurality and remoteness. Six units were purposively selected and 131 interviews were conducted with managers, staff and community members over 15 months. Analysis induced themes pertinent to remoteness and rurality. These included: perceived 'distance' between senior managers imposing change and the wider community of staff and residents; perceptions of community vulnerability; and tensions arising from working in small teams and living in small communities. The study provides useful insights for rural managers at a time of considerable service reconfiguration. 相似文献