首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13947篇
  免费   1600篇
  国内免费   39篇
耳鼻咽喉   252篇
儿科学   461篇
妇产科学   309篇
基础医学   2159篇
口腔科学   249篇
临床医学   1845篇
内科学   2925篇
皮肤病学   187篇
神经病学   900篇
特种医学   490篇
外科学   1764篇
综合类   314篇
一般理论   12篇
预防医学   1534篇
眼科学   157篇
药学   1117篇
中国医学   4篇
肿瘤学   907篇
  2021年   196篇
  2020年   127篇
  2019年   203篇
  2018年   230篇
  2017年   197篇
  2016年   193篇
  2015年   223篇
  2014年   299篇
  2013年   454篇
  2012年   637篇
  2011年   657篇
  2010年   358篇
  2009年   324篇
  2008年   546篇
  2007年   648篇
  2006年   588篇
  2005年   602篇
  2004年   577篇
  2003年   597篇
  2002年   523篇
  2001年   473篇
  2000年   523篇
  1999年   458篇
  1998年   202篇
  1997年   206篇
  1996年   175篇
  1995年   179篇
  1994年   153篇
  1993年   136篇
  1992年   356篇
  1991年   338篇
  1990年   330篇
  1989年   340篇
  1988年   288篇
  1987年   291篇
  1986年   262篇
  1985年   268篇
  1984年   179篇
  1983年   153篇
  1982年   128篇
  1981年   107篇
  1980年   101篇
  1979年   207篇
  1978年   137篇
  1977年   109篇
  1976年   105篇
  1974年   111篇
  1973年   100篇
  1972年   101篇
  1971年   94篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
31.
Objective Detection of HPV DNA in oral and genital lesions of a heterosexual male. 4 months after oral and vaginal intercourse with a woman with vulvar warts. Passible modes of acquisition of oral HPV infection in the male sexual partner are discussed. Setting Genitourinary Medicine clinic. Methods Polymerase chain reaction amplification of genomic DNA from oral and genital lesions. HPV DNA typing by dot blot hybridization. Results HPV DNA types 6 and 11 were identified in a polypoid tongue lesion and in a penile wart from the male sexual partner. Conclusions The acquisition of oral HPV infection in the male sexual partner may have resulted from genital-oral HPV transfer, either by direct contact with vulvar warts or by digital self-inoculation.  相似文献   
32.
BACKGROUND & AIMS: Nutrients and properties of lipases affect survival of lipolytic activity during aboral gastrointestinal transit. Whether different doses and formulations of bacterial lipase and diets affect steatorrhea was tested in pancreatic-insufficient dogs. METHODS: A dose of 0-600,000 IU of powdered and 135,000 and 300,000 IU of liquid bacterial lipase was given with a standard meal to 5 dogs with ligated pancreatic ducts. In 4 dogs, 0 or 300,000 IU (normal 6-hour postprandial amount) of powder bacterial lipase was also given with five meals containing 850 kcal with different nutrient caloric densities (mixture design). Coefficients of fat absorption during 72- hour fecal balance studies were used to assess treatments. RESULTS: With the standard meal, powder bacterial lipase reduced steatorrhea in a dose-dependent manner (P = 0.03), and 135,000 and 300,000 IU of the liquid form decreased steatorrhea more than powder bacterial lipase (P = 0.017 and 0.057, respectively). Coefficients of fat absorption with 300,000 IU of powder bacterial lipase correlated (r2 = 0.79; P < 0.001) with increasing proportions of fat calories in diets. CONCLUSIONS: Liquid bacterial lipase decreases steatorrhea more than powder, and 300,000 IU of powder bacterial lipase ingested with high-fat meals corrects canine pancreatic steatorrhea. The combination of adequate mixing of small amounts (milligrams) of bacterial lipase and high-fat meals abolishes canine steatorrhea and may abolish human pancreatic steatorrhea. (Gastroenterology 1997 Jun;112(6):2048-55)  相似文献   
33.
Indications and results of relaxing retinotomy   总被引:8,自引:0,他引:8  
The authors report their results of a consecutive series of 40 eyes undergoing relaxing retinotomy during vitrectomy to achieve retinal reattachment for the following indications: proliferative vitreoretinopathy (PVR), 21 eyes (52%); trauma, 10 eyes (25%); diabetic retinopathy, 6 eyes (15%); and expulsive choroidal hemorrhage, 3 eyes (8%). Thirty eyes (75%) had undergone previous vitreoretinal procedures. Extended tamponade was achieved in all cases with either silicone oil (27 eyes, 68%) or long-acting gas (13 eyes, 32%). Retinotomy size ranged from 45 degrees to 360 degrees. Intraoperative retinal attachment was possible in all eyes with 33 (83%) achieving total or subtotal retinal attachment including the macula for 5 months or more. Twenty-seven eyes (68%) achieved 3/200 visual acuity or better and 10 (37%) achieved 20/400 or better. Thirteen eyes (32%) failed to achieve 3/200 visual acuity secondary to recurrent detachment (18%), corneal decompensation (8%), macular dysfunction (5%), and glaucoma (3%).  相似文献   
34.
35.
36.
37.
The affinity of morphine, normorphine, methadone, Tyr-D-Ala-Gly-MePhe-NH(CH2)2(N-O)(CH3)2 (RX 783030), [D-Ala2,D-Leu5]enkephalin (DADLE), ketazocine and ethylketocyclazocine (EKC) were determined for their pharmacological receptors in two bioassay tissues, the guinea-pig ileum and the mouse vas deferens (MVD). The method involved the use of the irreversible antagonist, beta-chlornaltrexamine (beta-CNA), and the method of partial receptor blockade. The agonist concentration-effect curves were displaced to the right with decreasing maximum effect, a pattern typical of partial, irreversible blockade of receptors. The concentrations of beta-CNA required to produce a rightward displacement in the concentration-effect curves for different agonists, ranged between 2 and 3000 nM. No similarity was found between the IC50 and the dissociation constant (KA), values predicted to be equivalent only if a linear relationship exists between receptor occupation and observed effect; the dissociation constant for the agonists were between 3 and 218 times larger than the IC50 values. When methadone was used as the agonist in the guinea-pig ileum, beta-CNA produced parallel displacement of the concentration-effect curve, regardless of the blocking concentration chosen, preventing the determination of KA for this agonist, in this tissue; this problem was not encountered in the mouse vas deferens. The KA of morphine, RX 783030 and ketazocine were found not to differ in the guinea-pig ileum and mouse vas deferens. As expected, DADLE had significantly different affinity in the two tissues, showing 117-fold lower affinity in the guinea-pig ileum. Surprisingly, the normorphine affinity was found to be 7-fold higher in the guinea-pig ileum. While the difference in affinity of DADLE may be due to the suggested lack of functional delta receptors in the guinea-pig ileum, the difference in affinity seen with normorphine, but not morphine, in the two tissues is difficult to explain. Taken together with the insensitivity of methadone to beta-CNA blockade in the guinea-pig ileum, but not mouse vas deferens, the difference in the affinity of normorphine in these tissues may suggest the possibility of differences in local milieu of mu receptors or of mu receptor subtypes in the two tissues. The results provide fundamental information regarding opioid agonist affinity in two standard bioassays in vitro, and support the view of (1) a difference in receptors activated by DADLE in the guinea-pig ileum (mu) and mouse vas deferens (delta), as well as (2) possible differences in mu-receptors in these tissues.  相似文献   
38.
39.
The rapid movement of information technologies into health care organizations has raised managerial concern regarding the capability of today's institutions to satisfactorily manage their introduction. Indeed, several health care institutions have consumed huge amounts of money and frustrated countless people in wasted information systems implementation efforts. Unfortunately, there are no easy answers as to why so many health informatics projects are not more successful. In this light, the aim of this study is to provide a deeper understanding of how clinical information systems are being implemented by emphasizing research efforts on the dynamic nature of the process, that is, the “how” and “why” of what happened. Using a case study methodology, we examined the implementation of a patient charting system in the Burn Center of a large, not-for-profit, teaching hospital. Based on an in-depth examination of this implementation, several insights are offered to those who have responsibility for managing complex and risky clinical information system implementation projects.  相似文献   
40.
A total of 277 third and fourth year medical students and 304 house officers and senior house officers were asked to prioritise the content and methods of clinical teaching. Response rates were poor, but similar to that in market surveys. Bedside teaching and medical clerking were considered the most valuable methods of teaching and training in practical procedures such as venepunctures and urinary catheterisation was seen as valuable. The design of new curricula in medical education will need to accommodate the views of its clients.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号