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   54765篇
  免费   4870篇
  国内免费   87篇
耳鼻咽喉   598篇
儿科学   1547篇
妇产科学   1116篇
基础医学   7098篇
口腔科学   1213篇
临床医学   6230篇
内科学   10538篇
皮肤病学   831篇
神经病学   6087篇
特种医学   2636篇
外国民族医学   4篇
外科学   7894篇
综合类   797篇
一般理论   38篇
预防医学   4814篇
眼科学   1332篇
药学   3521篇
  2篇
中国医学   59篇
肿瘤学   3367篇
  2022年   434篇
  2021年   967篇
  2020年   554篇
  2019年   834篇
  2018年   960篇
  2017年   837篇
  2016年   912篇
  2015年   993篇
  2014年   1332篇
  2013年   1940篇
  2012年   2767篇
  2011年   2865篇
  2010年   1598篇
  2009年   1401篇
  2008年   2411篇
  2007年   2617篇
  2006年   2416篇
  2005年   2194篇
  2004年   2125篇
  2003年   1950篇
  2002年   1982篇
  2001年   1610篇
  2000年   1608篇
  1999年   1429篇
  1998年   567篇
  1997年   514篇
  1996年   492篇
  1995年   471篇
  1994年   411篇
  1992年   1193篇
  1991年   1191篇
  1990年   1122篇
  1989年   1112篇
  1988年   922篇
  1987年   1050篇
  1986年   963篇
  1985年   977篇
  1984年   766篇
  1983年   628篇
  1982年   403篇
  1981年   372篇
  1980年   375篇
  1979年   710篇
  1978年   536篇
  1977年   447篇
  1976年   467篇
  1975年   400篇
  1974年   525篇
  1973年   465篇
  1972年   395篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
51.
A prospective study was done on Indiana University freshman football players to determine if the incidence of lumbar spondylolysis and spondylolisthesis followed the pattern of previous studies. Using x-ray film evaluation, 145 freshman players were followed through their careers from 1978 to 1983. As in previous studies, a higher percentage (15.2%) of the defect was found than exists in the general population. However, only 2.4% of these players developed the problem in college, a much lower figure than previously found. Affected team members played a variety of positions. In addition to spondylolysis, some other problems, such as spina bifida occulta, were found. Theories on the cause of spondylolysis and spondylolisthesis are reviewed, and preventive suggestions such as more careful training and weight lifting are presented.  相似文献   
52.
53.
54.
As the biological width is established around neighboring implants, there is a flattening of the interimplant bone and a change in the position of the soft tissue. As a result, a normal progression of papilla from natural teeth through the adjacent implant area is lost. This presentation describes various techniques and strategies to improve the aesthetic outcome of anterior implant restorations, together with the use of a scalloped implant designed to sustain the interdental bony peaks, and in doing so, maintain the interimplant papillae.  相似文献   
55.
Isolates of Haemophilus influenzae type b (Hib) can be divided into three antigenic groups based on their reactivities with a set of two monoclonal antibodies (MAbs) directed against epitopes in the oligosaccharide region of Hib lipooligosaccharide (LOS) (P. A. Gulig, C. C. Patrick, L. Hermanstorfer, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 55:513-520, 1987). Approximately 24% of Hib strains react with both of these LOS-specific MAbs. Immunoprecipitation experiments involving several of these strains indicated that the epitopes recognized by these MAbs resided in two different LOS molecules, both of which were synthesized by these particular Hib strains. In addition, Western blot (immunoblot) analysis of proteinase K-treated cell extracts of these strains that had been subjected to sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis revealed two different LOS staining patterns when they were probed independently with the two MAbs. Colony blot radioimmunoassay of hundreds of colonies of one of these Hib strains showed that each colony bound both MAbs. Immune electron microscopy confirmed that individual cells of this same Hib strain expressed both types of LOS molecule at the same time. An antibody accessibility radioimmunoassay was used to show that different Hib strains of this type varied in the relative amounts of each of the two MAbs that they could bind to their cell surfaces. These findings indicate that some Hib strains can synthesize two antigenically distinct LOS molecules simultaneously.  相似文献   
56.
In a study of rock music preferences, listening/watching behavior, and views on destructive rock lyrics, 894 adolescents in grades 9 through 12 in rural, urban, suburban public, and metropolitan parochial schools were administered a questionnaire. Demographic information on parents was also collected. It was found that 17.5% of the students were fans of rock music with lyrics that promote homicide, suicide, or satanic practices (HSSR). Loglinear and multiple regression analyses were used to analyze the data. Parents' marital status, student sex, race, and school environment (urban, rural, suburban, etc.) were found to be significant predictors of HSSR status. As compared with non-HSSR fans, the HSSR fans were more likely to have parents who were “Never married” or “Remarried” and less likely to have parents in the “married” category. The HSSR fans were more likely to be male, white, and enrolled in urban schools but not parochial schools than expected; HSSR status also significantly predicted other music-related attitudes and behaviors. The HSSR fans reported liking both the sound and the lyrics of rock music more often than did non-HSSR fans, as did females and urban students. The HSSR fans more often felt that children under 10 years of age should be allowed to listen to HSSR lyrics, and they more frequently expressed the conviction that HSSR music does not affect adolescents' homicidal or self-destructive behavior. The HSSR fans and females reported more nearly complete knowledge of lyrics than did non-HSSR fans and males. The HSSR fans reported that they watch more MTV than did any other group except rural students.  相似文献   
57.
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported.  相似文献   
58.
We appreciate to read Dr Komócsís comments toour article entitled ‘Low response to clopidogrel is associatedwith cardiovascular outcome after coronary stent implantation’. He critically remarked the mortality rate in our study. Indeed,we found an all-cause mortality of 5.2% within 3 months (cardiovascularmortality: 3.9%). However, it is worthy to note that we investigatedan unselected patient collective with moderate- to  相似文献   
59.
The diagnosis of hysteria is often incorrect and must be made with great caution. A retrospective study demonstrates that an erroneous diagnosis of hysteria is most likely to be given to females, the psychiatrically ill, patients who embellish and patients who present plausible psychogenic explanations for their illness. Movement disorders and paralysis are the neurologic disorders most frequently mislabeled as hysteria.  相似文献   
60.
PURPOSE: The use of gefitinib, the first drug approved to inhibit the epidermal growth factor receptor tyrosine kinase, is indicated in patients with non-small-cell lung cancer with tumors progressive after chemotherapy. The unique mechanism of action of this agent leads to distinctive patterns of response and toxicity in persons with lung cancer. Many of the principles of management relevant to gefitinib are distinct from those with conventional cytotoxic drugs. To meet this need, we present practical guidelines on the use of gefitinib in patients with non-small-cell lung cancer. METHODS: This article reviews gefitinib's indications, dosing, response phenomena, and patterns of relapse in individuals with radiographic response. RESULTS: We present our recommendations for the management of rash and diarrhea caused by this agent. CONCLUSION: This information can guide practitioners and help them inform their patients about what to expect when they receive gefitinib.  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