全文获取类型
收费全文 | 19938篇 |
免费 | 1749篇 |
国内免费 | 134篇 |
专业分类
耳鼻咽喉 | 217篇 |
儿科学 | 568篇 |
妇产科学 | 471篇 |
基础医学 | 2464篇 |
口腔科学 | 462篇 |
临床医学 | 2412篇 |
内科学 | 3529篇 |
皮肤病学 | 211篇 |
神经病学 | 1956篇 |
特种医学 | 585篇 |
外科学 | 2540篇 |
综合类 | 604篇 |
一般理论 | 24篇 |
预防医学 | 2124篇 |
眼科学 | 474篇 |
药学 | 1564篇 |
中国医学 | 16篇 |
肿瘤学 | 1600篇 |
出版年
2022年 | 129篇 |
2021年 | 262篇 |
2020年 | 183篇 |
2019年 | 256篇 |
2018年 | 335篇 |
2017年 | 256篇 |
2016年 | 302篇 |
2015年 | 335篇 |
2014年 | 430篇 |
2013年 | 676篇 |
2012年 | 990篇 |
2011年 | 965篇 |
2010年 | 546篇 |
2009年 | 498篇 |
2008年 | 886篇 |
2007年 | 1010篇 |
2006年 | 880篇 |
2005年 | 885篇 |
2004年 | 866篇 |
2003年 | 796篇 |
2002年 | 820篇 |
2001年 | 624篇 |
2000年 | 585篇 |
1999年 | 519篇 |
1998年 | 303篇 |
1997年 | 231篇 |
1996年 | 256篇 |
1995年 | 221篇 |
1994年 | 205篇 |
1993年 | 194篇 |
1992年 | 403篇 |
1991年 | 389篇 |
1990年 | 429篇 |
1989年 | 388篇 |
1988年 | 378篇 |
1987年 | 365篇 |
1986年 | 355篇 |
1985年 | 305篇 |
1984年 | 242篇 |
1983年 | 196篇 |
1982年 | 138篇 |
1981年 | 124篇 |
1979年 | 236篇 |
1978年 | 158篇 |
1977年 | 137篇 |
1976年 | 128篇 |
1975年 | 146篇 |
1974年 | 165篇 |
1973年 | 131篇 |
1972年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
Mini-Mental State Examination (MMSE) scores were studied in an ambulatory elderly population to identify correlates with self-reported signs, symptoms, diseases, drugs and laboratory values. A total of 1,264 subjects were studied including 844 women and 420 men. In this study, 5.0% of men and 5.3% of women scored less than 24 on the MMSE. A linear-regression model revealed eleven factors of significance in predicting scores on the MMSE. The most important predictors were age (p less than 0.0001), self-reported memory loss (p less than 0.0001), complaints of swollen feet or ankles (p less than 0.0010), the total number of diseases reported (0.0006) and the serum lactate dehydrogenase concentration (p less than 0.0098). Results suggest that cognitive function in the elderly is not related to the general level of health or consistently affected by specific disease states. 相似文献
43.
Long H. Phan Michael J. Hickey Zahid B. M. Niazi Alastair G. Stewart 《Microsurgery》1994,15(10):703-707
Nitric oxide (NO), originally identified as the mediator of endothelial-dependent relaxation of vascular smooth muscle, is now known to also have cytotoxic effects under certain conditions. Thus, we have investigated the effects of inhibition of NO synthesis on ischemia/reperfusion injury in the rabbit rectus femoris muscle. Three and a half hours of ischemia and 24 hours of reperfusion resulted in a 56% loss of viability. In muscles receiving an infusion of the nitric oxide synthase inhibitor, L-NIO (30 μM), the loss of viability was reduced to 15%. Post-ischemic blood flow was increased in muscles receiving a saline infusion, whereas there was a marked decrease in blood flow for at least the first 60 minutes of reperfusion in muscles treated with L-NIO (30 μM). The increase in myeloperoxidase levels (indicative of neutrophil accumulation) following 24 hours of reperfusion was attenuated with L-NIO infusion by approximately 50% and the reperfusion-induced edema was also attenuated in L-NIO treated muscle. These findings suggest that endogenous NO production during ischemia/reperfusion injury may be deleterious to muscle survival. © 1994 Wiley-Liss, Inc. 相似文献
44.
45.
The functioning and well-being of depressed patients. Results from the Medical Outcomes Study 总被引:47,自引:10,他引:37
K B Wells A Stewart R D Hays M A Burnam W Rogers M Daniels S Berry S Greenfield J Ware 《JAMA》1989,262(7):914-919
We describe the functioning and well-being of patients with depression, relative to patients with chronic medical conditions or no chronic conditions. Data are from 11,242 outpatients in three health care provision systems in three US sites. Patients with either current depressive disorder or depressive symptoms in the absence of disorder tended to have worse physical, social, and role functioning, worse perceived current health, and greater bodily pain than did patients with no chronic conditions. The poor functioning uniquely associated with depressive symptoms, with or without depressive disorder, was comparable with or worse than that uniquely associated with eight major chronic medical conditions. For example, the unique association of days in bed with depressive symptoms was significantly greater than the comparable association with hypertension, diabetes, and arthritis. Depression and chronic medical conditions had unique and additive effects on patient functioning. 相似文献
46.
47.
Carol Sigelman Tamara Didjurgis Brenda Marshall Frank Vargas Amanda Stewart 《Child psychiatry and human development》1992,22(4):265-276
Native American, Hispanic, and Anglo sixth graders reacting to an example of teenage problem drinking expressed similar beliefs and attitudes in many respects. However, Native American children viewed the problem as less serious, subscribed more to a disease theory of alcoholism, attributed less causal responsibility to the individual, and adopted a less aggressive approach toward treatment than did Hispanic, and especially Anglo, children. Their less conventional value orientations accounted for all these differences except their stronger endorsement of a disease theory of problem drinking. 相似文献
48.
49.
Indomethacin promotes germinal matrix microvessel maturation in the newborn beagle pup. 总被引:1,自引:0,他引:1
L R Ment W B Stewart T A Ardito E Huang J A Madri 《Stroke; a journal of cerebral circulation》1992,23(8):1132-1137
BACKGROUND AND PURPOSE: Although indomethacin has been demonstrated to prevent germinal matrix and intraventricular hemorrhage in clinical and animal studies, the mechanism of action of this agent to prevent hemorrhage remains unclear. Previous studies have demonstrated both that the microvessels in the germinal matrix of newborn beagle pups undergo basement membrane maturation during the first 4 postnatal days and that indomethacin may promote laminin deposition in tumor cell culture systems. METHODS: We employed the newborn beagle pup model to test the hypothesis that indomethacin may stimulate laminin deposition in germinal matrix microvessels. Newborn pups were randomized to receive either 0.1 mg/kg/dose i.p. indomethacin or an equal volume of saline diluent. Pups received doses of study medication once a day for 1, 2, or 3 days and were studied on postnatal days 1, 2, 3, or 4. Pups were anesthetized and systemically perfused with buffered formalin; the brains were removed and prepared for immunohistochemical study. RESULTS: Sections stained with Bandeiraea lectin demonstrated that there was no difference in germinal matrix vessel density among the postnatal ages studied; similarly, there were no differences in vessel density between saline- and indomethacin-treated animals at any postnatal age. Quantification of germinal matrix stained intensity by confocal microscopy demonstrated significant increases in indomethacin-treated pups for both laminin staining at postnatal days 2 (p = 0.05) and 3 (p = 0.0009) and type V collagen staining at postnatal day 2 (p = 0.011). Although staining for beta 1 integrins increased across postnatal ages, there were no differences between saline- and indomethacin-treated animals. CONCLUSIONS: These data suggest that indomethacin may stimulate basement membrane deposition in the germinal matrix microvessels of newborn beagle pups to prevent germinal matrix and/or intraventricular hemorrhage. 相似文献
50.
The use of 5-fluorouracil in patients following combined trabeculectomy and cataract extraction 总被引:1,自引:0,他引:1
We studied the effect of postoperative administration of subconjunctival 5-fluorouracil in maintaining postoperative filtration following combined trabeculectomy and extracapsular cataract extraction with posterior chamber lens implantation. Three months postoperatively, the mean intraocular pressure in 15 patients who had received 5-fluorouracil was 13.1 +/- 3.2 mm Hg; in 17 control patients, it was 13.0 +/- 3.0 mm Hg (P greater than .05). The mean number of postoperative medicines in the study patients was 0.7; in the control patients, 0.8 (P greater than .05). Bleb appearance and improvement in visual acuity were similar in the two groups. This study does not support the routine use of 5-fluorouracil in patients who have undergone combined trabeculectomy and extracapsular cataract extraction. 相似文献