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   410838篇
  免费   51464篇
  国内免费   700篇
耳鼻咽喉   6090篇
儿科学   14202篇
妇产科学   7934篇
基础医学   62220篇
口腔科学   14229篇
临床医学   36466篇
内科学   97562篇
皮肤病学   15913篇
神经病学   41223篇
特种医学   11474篇
外国民族医学   102篇
外科学   53676篇
综合类   1508篇
一般理论   125篇
预防医学   36116篇
眼科学   8061篇
药学   29222篇
中国医学   2194篇
肿瘤学   24685篇
  2023年   1961篇
  2022年   2125篇
  2021年   7514篇
  2020年   8407篇
  2019年   17068篇
  2018年   19895篇
  2017年   17072篇
  2016年   17680篇
  2015年   18555篇
  2014年   19426篇
  2013年   24845篇
  2012年   27207篇
  2011年   27671篇
  2010年   20094篇
  2009年   13857篇
  2008年   21817篇
  2007年   22263篇
  2006年   20460篇
  2005年   20037篇
  2004年   18512篇
  2003年   17064篇
  2002年   16265篇
  2001年   9768篇
  2000年   10294篇
  1999年   8366篇
  1998年   1439篇
  1997年   1144篇
  1996年   1074篇
  1995年   925篇
  1992年   4278篇
  1991年   3746篇
  1990年   3545篇
  1989年   3142篇
  1988年   2901篇
  1987年   2715篇
  1986年   2623篇
  1985年   2344篇
  1984年   1740篇
  1983年   1445篇
  1979年   1513篇
  1978年   1040篇
  1977年   962篇
  1975年   1052篇
  1974年   1258篇
  1973年   1309篇
  1972年   1207篇
  1971年   1212篇
  1970年   1120篇
  1969年   1172篇
  1968年   1042篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
Mortality prognostic factors in chest injury   总被引:2,自引:0,他引:2  
1,026 multiple trauma patients (P) were compared to P with chest injuries (PCT) (407). Severity indices were related to type of thoracic injury and mortality. The Injury Severity Score (ISS), Glasgow Coma Scale (GCS), Trauma Score (TS), CHOP, and the Respiratory Index (RI) were used. The mortality rate of P was 27.1% but increased to 32.9% for PCT (p less than 0.05). We noted that mortality rate was highly dependent on major chest trauma: 68.6% for flail chest (FC), 56% for lung contusion (LC), 42.3% for hemothorax (HA), and 38.1% for pneumothorax (PN). ISS and RI scores for PCT survivors were greater than ISS + RI scores for P survivors (p less than 0.05 and p less than 0.01). ISS values for LC, HA, and PN PCT survivors were greater than the ISS of P survivors (p less than 0.01). Nonsurviving PCTs, especially those with lung contusion, showed a highly significant increase in ISS and RI scores.  相似文献   
75.
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue.  相似文献   
76.
Most of the nearly 1,000 fatal bicycle-related injuries annually could be prevented if riders used safety helmets. Helmet use by adult bicyclists has received relatively little attention because educational campaigns to promote helmet use generally focus on children. Helmet use by adult and child bicyclists at 120 suburban and rural sites in three Maryland counties was observed on two Saturdays in 1990-91 during an evaluation of the impact of a mandatory helmet law. Concordance or discordance of helmet use within various groups of bicyclists--adults only, adults with children, and children only--was recorded. Helmet use among 2,068 adult bicyclists was 49 percent, 51 percent, and 74 percent in the three counties. In two counties combined, 52 percent (365 of 706) of solo adult bicyclists wore helmets compared with only 5 percent (5 of 94) of solo child bicyclists (P < .001). Helmet use or nonuse was concordant among 87 percent of 277 adult-adult pairs, 94 percent of 50 child-child pairs, and 91 percent of 32 adult-child pairs of bicyclists observed. Concordance rates of helmet use or nonuse were similarly high among pairs of adult bicyclists of the same or mixed sexes. These data are consistent with the concept that both adults and children tend to adopt the helmet-wearing behaviors of their companions. Public health efforts focused on adults should encourage helmet use by adult bicyclists both to prevent head injuries and to provide a role model for children.  相似文献   
77.
The present authors investigated the excretion, distribution and pharmacokinetics of the novel potential antirheumatic agent flobufen and its active metabolite after p.o. and i.v. doses of 2, 10 and 50 mg/kg administered to rats. The drug is resorbed well from the digestive tract and mostly it is metabolized to the principal metabolite M, which is only slowly excreted from the organism mainly by renal clearance. Within the whole dose range the kinetics of the drug is linear. Binding of flobufen and M to proteins is high (95-99%). The highest concentrations of radioactive metabolites (mostly M) were found in the plasma, liver, lungs, kidneys, connective tissue and inflammatory foci. The penetration of metabolites through the placenta and excretion in human milk are relatively important.  相似文献   
78.
79.
80.
We report a prevalence study of the best visual acuity in the affected eye of 100 selected patients with herpetic keratitis seen during a two-year period. Sixty-two patients retained an acuity of 6/9 or better without requiring penetrating keratoplasty (PK). The prevalence of reduced visual acuity severe enough to warrant PK was 33%. Patients requiring PK for whom full clinical records were available suffered a mean of 6.8 episodes of keratitis. In this group of patients the vision of 18 fell from 6/6 to 6/60 over a mean period of 8.5 years. Once visual acuity was permanently reduced to 6/12, 78% of patients proceeded to lose vision to 6/60. Unilateral visual impairment occurs in at least a third of patients with severe herpetic keratitis. Once vision falls permanently to 6/12, the long-term prognosis for vision appears to be poor.  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