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   5451篇
  免费   441篇
  国内免费   32篇
耳鼻咽喉   22篇
儿科学   172篇
妇产科学   123篇
基础医学   797篇
口腔科学   305篇
临床医学   629篇
内科学   1023篇
皮肤病学   171篇
神经病学   425篇
特种医学   384篇
外科学   704篇
综合类   142篇
一般理论   1篇
预防医学   408篇
眼科学   87篇
药学   380篇
中国医学   7篇
肿瘤学   144篇
  2021年   67篇
  2020年   51篇
  2019年   72篇
  2018年   107篇
  2017年   75篇
  2016年   74篇
  2015年   80篇
  2014年   119篇
  2013年   188篇
  2012年   191篇
  2011年   155篇
  2010年   128篇
  2009年   121篇
  2008年   132篇
  2007年   187篇
  2006年   189篇
  2005年   153篇
  2004年   146篇
  2003年   134篇
  2002年   154篇
  2001年   142篇
  2000年   134篇
  1999年   133篇
  1998年   128篇
  1997年   130篇
  1996年   136篇
  1995年   97篇
  1994年   113篇
  1993年   109篇
  1992年   116篇
  1991年   117篇
  1990年   106篇
  1989年   135篇
  1988年   120篇
  1987年   108篇
  1986年   113篇
  1985年   84篇
  1984年   95篇
  1983年   63篇
  1982年   62篇
  1981年   53篇
  1980年   67篇
  1979年   55篇
  1978年   53篇
  1977年   56篇
  1976年   55篇
  1965年   56篇
  1964年   56篇
  1963年   48篇
  1960年   67篇
排序方式: 共有5924条查询结果,搜索用时 15 毫秒
31.
PROBLEM--Occupational exposure to human immunodeficiency virus (HIV) disease is a problem of concern to all health care workers, especially those in large urban teaching hospitals with large numbers of HIV-positive patients. METHOD--The self-reported incidence of needlesticks and other exposures to patients' blood and body fluids in 550 medical students and residents at the Los Angeles County-University of Southern California Medical Center during the 1989 through 1990 training year was studied by means of an anonymous survey. RESULTS--Seventy-one percent of respondents reported one or more needlesticks or other exposures during the training year. Surgical residents had a sixfold greater rate of occupational exposure compared with medicine residents and were significantly more likely to experience suture needlesticks, cuts, open wound contamination, and mucous membrane exposure. Medical students generally were at somewhat lower risk compared with residents, but had greater rates of hollow-needle puncture accidents. No trend was found for accidental exposure by level of residency training. The known HIV-positive exposure rate for students and residents was 9.5% per person per year. Only 9% of exposures were actually reported to the health center. CONCLUSIONS--Based on the rate of exposures reported, numbers of known and estimated HIV-positive patients, and previously published HIV seroconversion rates, we would expect an annual rate of HIV seroconversion rates, we would expect an annual rate of HIV seroconversion as a result of occupational exposures of between 27 and 46 per 100,000. This rate is similar to the leading cause of death in this age group--motor vehicle accidents--and is equivalent to one student or resident in this medical center seroconverting every 2 to 3 years. Although only a portion of accidental exposures are regarded as preventable, these data emphasize the importance of increased efforts toward improved education, prevention, and accessibility of protective equipment.  相似文献   
32.
While there is growing awareness for the need to examine the etiology of problem behaviors across cultural, racial, socioeconomic, and gender groups, much research tends to assume that constructs are equivalent and that the measures developed within one group equally assess constructs across groups. The meaning of constructs, however, may differ across groups or, if similar in meaning, measures developed for a given construct in one particular group may not be assessing the same construct or may not be assessing the construct in the same manner in other groups. The aims of this paper were to demonstrate a process of testing several forms of equivalence including conceptual, functional, item, and scalar using different methods. Data were from the Cross-Cultural Families Project, a study examining factors that promote the healthy development and adjustment of children among immigrant Cambodian and Vietnamese families. The process described in this paper can be implemented in other prevention studies interested in diverse groups. Demonstrating equivalence of constructs and measures prior to group comparisons is necessary in order to lend support of our interpretation of issues such as ethnic group differences and similarities.  相似文献   
33.
34.
35.
The neurotoxic effects of single subcutaneous injections of1000 mg triphenyl phosphite (TPP)/kg body weight were investigatedin White Leghorn hens. At 7 days postexposure, birds began toshow signs of mild to moderate ataxia that progressed to severeataxia and paralysis at 21 days. Inhibition of whole brain neuropathytarget esterase was 85% at 48 hr and 73% by 21 days postexposure.After postexposure periods of 7, 14, and 21 days, hens werekilled and their brains and spinal cords were examined for degeneratingaxons and terminals using the Fink-Heimer silver impregnationmethod. A small amount of degeneration was noted at 7 days.By 21 days, dense degeneration was noted in the spinal graymatter and funiculi. Degeneration was also present in the granularcell layer of cerebellar folia I-VI and in nuclei and fibertracts of the medulla. Moderate to dense degeneration was alsoseen in several forebrain and midbrain areas including the paleostriatum,ansa lenticularis, the dorsointermediate thalamic nucleus, lateralspiriform, pedunculopontine tegmental, and lateral mesencephalicnuclei and in the deeper layers of the optic tectum. These resultsindicate that, in addition to affecting the spinal cord andbrainstem, exposure to TPP also damages higher order centersresponsible for processing and integrating sensorimotor, visual,and auditory information.  相似文献   
36.
The incidence, risk factors, and prognosis for Mycobacterium tuberculosis (MTB) infection have not been reported in a national population of renal transplant recipients. We performed a retrospective cohort study of 15,870 Medicare patients who received renal transplants from January 1, 1998 to July 31, 2000. Cox regression analysis derived adjusted hazard ratios (AHR) for factors associated with a diagnosis of MTB infection (by Medicare Institutional Claims) and the association of MTB infection with survival. There were 66 renal transplant recipients diagnosed with tuberculosis infection after transplant (2.5 cases per 1000 person years at risk, with some falling off of cases over time). The most common diagnosis was pulmonary TB (41 cases). In Cox regression analysis, only systemic lupus erythematosus (SLE) was independently associated with TB. Mortality after TB was diagnosed was 23% at 1 year, which was significantly higher than in renal transplant recipients without TB (AHR, 4.13, 95% CI, 2.21, 7.71, p < 0.001). Although uncommon, MTB infection is associated with a substantially increased risk of mortality after renal transplantation. High-risk groups, particularly those with SLE prior to transplant, might benefit from intensified screening.  相似文献   
37.
38.
39.
The general public of the City of Bergen, Norway was Invitedto participate in a cholesterol screening programme in October1988. Participants received the results of the cholesterol screeningand nutritional information from trained health personnel. Ashort questionnaire was mailed to all 354 participants 1–2weeks after the initial cholesterol screening. In March 1990,all participants were invited to have their cholesterol levelsre-examined. Psychosocial factors believed to be predictiveof future serum cholesterol changes were assessed at baselinealong with demographic variables. The majority of participants(61%) reduced their cholesterol level from October 1988 to March1990, and the average reduction in cholesterol level for thetotal population was 4.0%. Baseline cholesterol levels, beingconfident of one's own ability to change one's diet (self-efficacy),seeing heart disease risk reduction as very important, and maritalstatus were factors that significantly predicted successfulcholesterol reduction 18 months later.  相似文献   
40.
Postoperative radiation therapy in the management of lung cancer   总被引:1,自引:0,他引:1  
Postoperative radiation therapy for lung cancer is still controversial. In a 9-year period, 69 patients with non-oat-cell carcinoma of the lung (16% stage I, 26% stage II, and 58% stage III) received such therapy. The radiation dose was less than 5,000 cGy in 42 patients, 5,000-5,900 cGy in 16, and 6,000 cGy or more in 11; follow-up ranged from 24 to 64 months. Actuarial survival at 2 and 4 years was 50% and 16%, respectively, for squamous cell carcinoma, and 40% and 26% for adenocarcinoma. The 5-year survival for stages I, II, and III cancer was 29%, 17%, and 19%, respectively. Histologic findings and type of surgery did not affect survival, but the radiation dose apparently did. The 3-year survival for patients who received less than 6,000 cGy was 35%, compared with 73% for patients who received higher doses. In eight patients, treatment failed within the irradiated volume: all had received doses of less than 6,000 cGy, and the volume in three was judged to be inadequate.  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