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   14876篇
  免费   1336篇
  国内免费   102篇
耳鼻咽喉   82篇
儿科学   617篇
妇产科学   379篇
基础医学   1955篇
口腔科学   427篇
临床医学   1783篇
内科学   2973篇
皮肤病学   201篇
神经病学   1106篇
特种医学   818篇
外科学   2040篇
综合类   426篇
一般理论   11篇
预防医学   1614篇
眼科学   158篇
药学   911篇
  2篇
中国医学   8篇
肿瘤学   803篇
  2021年   190篇
  2020年   121篇
  2019年   207篇
  2018年   249篇
  2017年   191篇
  2016年   193篇
  2015年   247篇
  2014年   310篇
  2013年   465篇
  2012年   635篇
  2011年   663篇
  2010年   407篇
  2009年   396篇
  2008年   571篇
  2007年   683篇
  2006年   577篇
  2005年   562篇
  2004年   514篇
  2003年   469篇
  2002年   469篇
  2001年   443篇
  2000年   524篇
  1999年   460篇
  1998年   274篇
  1997年   288篇
  1996年   290篇
  1995年   266篇
  1994年   242篇
  1993年   223篇
  1992年   344篇
  1991年   353篇
  1990年   377篇
  1989年   343篇
  1988年   303篇
  1987年   294篇
  1986年   284篇
  1985年   291篇
  1984年   196篇
  1983年   153篇
  1982年   111篇
  1981年   115篇
  1980年   117篇
  1979年   157篇
  1978年   134篇
  1977年   119篇
  1976年   125篇
  1974年   124篇
  1973年   116篇
  1972年   116篇
  1971年   114篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
81.
82.
OBJECTIVE: We sought to determine whether the use of talc in genital hygiene increases the risk for epithelial ovarian cancer. METHODS: We interviewed 235 white women diagnosed with epithelial ovarian cancer between 1984-1987 at ten Boston metropolitan area hospitals and 239 population-based controls of similar race, age, and residence. RESULTS: Overall, 49% of cases and 39% of controls reported exposure to talc, via direct application to the perineum or to undergarments, sanitary napkins, or diaphragms, which yielded a 1.5 odds ratio (OR) for ovarian cancer (95% confidence interval [CI] 1.0-2.1). Among women with perineal exposure to talc, the risk was significantly elevated in the subgroups of women who applied it: 1) directly as a body powder (OR 1.7, 95% CI 1.1-2.7), 2) on a daily basis (OR 1.8, 95% CI 1.1-3.0), and 3) for more than 10 years (OR 1.6, 95% CI 1.0-2.7). The greatest ovarian cancer risk associated with perineal talc use was observed in the subgroup of women estimated to have made more than 10,000 applications during years when they were ovulating and had an intact genital tract (OR 2.8, 95% CI 1.4-5.4); however, this exposure was found in only 14% of the women with ovarian cancer. CONCLUSIONS: These data support the concept that a life-time pattern of perineal talc use may increase the risk for epithelial ovarian cancer but is unlikely to be the etiology for the majority of epithelial ovarian cancers.  相似文献   
83.
84.
85.
OBJECTIVE: Measurement of quality of life three months following critical illness, to assess impact on health expectations. DESIGN: Continuous quantitative study of patients admitted to a combined intensive and coronary care unit during a nine-month period. Questionnaires giving baseline information were completed soon after admission, and postal questionnaires incorporating the Nottingham Health Profile were sent to surviving patients three months following discharge from the unit. SETTING: District General Hospital. SUBJECTS: ICU sample included 60 patients, male n = 31, female n = 29. Twenty-nine patients received surgical treatment, 31 patients received medical treatment. Coronary Care Unit (CCU) sample included 112 patients, male n = 74, female n = 38. Fifty-four patients admitted following acute myocardial infarction (MI), 58 patients non-MI admission. MEASUREMENTS AND MAIN RESULTS: Hospital mortality for ICU patients was 31%, increasing to 34% at three months. Hospital mortality for CCU patients was 14%, increasing to 19% at three months. Significant differences in mean NHP scores between ICU and CCU patients were noted with higher CCU scores in the areas of sleep (p = 0.04), and social isolation (p = 0.01). Within the ICU group surgical patients had a higher mean NHP score in the area of pain (p = 0.02). There were no significant differences in the scores of male and female ICU patients. Within the CCU group non-MI patients had significantly higher mean scores than MI patients in the areas of energy (p = 0.007), pain (p = 0.04), emotion (p = 0.05), social isolation (p = 0.01) and physical ability (p = 0.003). Female CCU patients had higher mean NHP scores than male patients with significant differences in the areas of pain (p = 0.04), sleep (p = 0.009) and physical ability (p = 0.006). CONCLUSION: ICU patient quality of life three months after admission compares favourably with a corresponding group of CCU patients, particularly in areas of sleep and social isolation. CCU patients' general functional status deteriorated significantly compared to their pre-admission status. Critical illness is a costly area of medicine, but the results suggest that outcomes are beneficial in terms of quality of life for those surviving acute illness.  相似文献   
86.
SUMMARY. There are no current U.K. or international guidelines or regulations covering the production, processing and storage of haemopoietic cells such as to allow their engraftment following myeloablative therapy. This paper seeks to provide such guidelines. It enumerates how quality control and assurance can be applied to this area of transfusion medicine; procedural steps relating to bone marrow harvest on peripheral blood stem cell collection are outlined and recommended doses of nucleated cells suggested for both procedures. General specifications for identification, storage and transportation of bone marrow and peripheral blood stem cells are included and specific laboratory procedures related to the provision of haemopoietic cells for engraftment are outlined. Umbilical cord blood transplants and long-term bone marrow culture are alluded to but these are still in a research phase.  相似文献   
87.
An amplification of a highly unstable DNA element has been identified at the fragile X locus in Xq27.3. This sequence appears to be both the source of the primary mutation causing the fragile X syndrome, apparently having its causative effect through the methylation of the FMR-1 HTF island and the region of cytogenetic fragility. The direct analysis of the genotype of carrier and affected individuals can be used as a direct diagnosis tool which will improve both the accuracy and speed of diagnosis. The identification of hereditary unstable DNA in a disease with such a wide level of non-penetrance and variable phenotype may give clues as to the basis of non-penetrance in other human genetic disorders.  相似文献   
88.
L C St John  F P Bell 《Atherosclerosis》1991,86(2-3):139-144
In the present studies, arterial lipid metabolism was evaluated in the spontaneously hyperlipidemic obese Zucker rat (fa/fa), the lean Zucker rat (Fa/-), and the Sprague-Dawley (SD) rat. Mean serum cholesterol levels in the obese Zucker, lean Zucker and SD rats were 216 +/- 18 mg/dl, 145 +/- 14 mg/dl and 84 +/- 5 mg/dl, respectively. Arterial cholesterol content was in the same rank order as plasma cholesterol and ranged from a mean of 2.23 +/- 0.10 mg/gm wet wt. in the obese rats to 1.36 +/- 0.04 mg/gm wet wt. in the SD rats. The increased arterial sterol in the obese rats was associated with increased lipid metabolism activity. The in vitro incorporation of [14C]oleate into arterial cholesteryl esters was increased 3-4-fold (P less than 0.01) and incorporation into phospholipids and triglycerides was also elevated (P less than 0.001 and P less than 0.01, respectively). The arterial sterol content and arterial lipid metabolism pattern observed in obese Zucker rat aortas are similar to those found in vessels of other species undergoing atherogenic change.  相似文献   
89.
Two recently published multicentre trials have confirmed the overall benefit of carotid endarterectomy in symptomatic patients with severe carotid artery disease. The key to improving further the long-term advantages of carotid endarterectomy, however, remains the continued reduction of the initial operative risk. While the principal responsibility for this continues to be borne by the surgeon, specifically in reducing technical error, the time is perhaps approaching when he or she might also be able to apply some of the recent advances in cerebrovascular research to reduce operative morbidity still further in the future. This article summarizes the aetiology and pathophysiology of operation-related neurological deficits and reviews current approaches towards intraoperative monitoring, cerebral protection and assessment of quality control.  相似文献   
90.
We describe the occurrence of primary hyperaldosteronism in two sisters. Although this is only the second published report of familial Conn''s syndrome, it does have implications for the relatives of patients with Conn''s syndrome and these are discussed.  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