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   960230篇
  免费   58550篇
  国内免费   1094篇
耳鼻咽喉   12632篇
儿科学   31669篇
妇产科学   25032篇
基础医学   157739篇
口腔科学   25326篇
临床医学   83885篇
内科学   177141篇
皮肤病学   22463篇
神经病学   66988篇
特种医学   35249篇
外国民族医学   116篇
外科学   142478篇
综合类   15690篇
现状与发展   2篇
一般理论   219篇
预防医学   71529篇
眼科学   22607篇
药学   74446篇
  1篇
中国医学   2016篇
肿瘤学   52646篇
  2018年   9926篇
  2016年   8286篇
  2015年   9224篇
  2014年   12479篇
  2013年   18974篇
  2012年   26805篇
  2011年   29340篇
  2010年   17056篇
  2009年   15738篇
  2008年   27537篇
  2007年   29891篇
  2006年   29690篇
  2005年   28329篇
  2004年   27674篇
  2003年   26604篇
  2002年   25872篇
  2001年   43327篇
  2000年   44766篇
  1999年   36853篇
  1998年   9969篇
  1997年   8531篇
  1996年   8838篇
  1995年   8210篇
  1994年   7517篇
  1992年   27776篇
  1991年   28983篇
  1990年   29111篇
  1989年   28277篇
  1988年   25976篇
  1987年   25733篇
  1986年   24150篇
  1985年   23124篇
  1984年   17253篇
  1983年   14693篇
  1982年   8036篇
  1981年   7343篇
  1979年   16680篇
  1978年   12001篇
  1977年   9909篇
  1976年   9959篇
  1975年   11680篇
  1974年   13495篇
  1973年   12973篇
  1972年   12204篇
  1971年   11741篇
  1970年   10929篇
  1969年   10364篇
  1968年   9781篇
  1967年   8770篇
  1966年   7826篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Management of splenic injuries in children has evolved over the past two decades. Splenectomies or splenorrhaphies are now performed infrequently, with the majority of hemodynamically stable children with splenic injuries managed nonoperatively. This article reviews the imaging features of acute splenic injuries in children as well as the appearance of healing splenic injuries. Follow-up evaluation and outcomes in children with splenic injuries also are addressed.  相似文献   
92.
OBJECTIVE: To determine the most frequent clinical causes of a prolonged activated partial thromboplastin time (APTT) result, and to determine whether a new heparin-removal device (the Hepchek, Pall Biomedical, Glen Cove, NY 11542) is capable of efficiently detecting the causes of these values. DESIGN: A combination of chart review and laboratory testing comparing the criterion standard--the heparin chromogenic substrate assay--with the Hepchek. Laboratory investigations were blinded and controlled. SETTING: Inpatient, acute-care hospital. PATIENTS: A total of 1,000 hospital patients with a variety of hemostatic disorders. MAIN OUTCOME MEASURE: The extent to which the Hepchek accurately identified the etiology of a prolonged APTT result. RESULTS: The APTT was prolonged in 25.2% of samples. The presence of heparin in the sample was confirmed by chromogenic assay or by using the Hepchek heparin-removal filter. The presence of heparin was confirmed in 12.8% of all samples and in more than 50% of all abnormal samples. The cause of the abnormal APTT was often unappreciated by the clinician. Bayesian analysis of the Hepchek's ability to diagnose heparin correctly as the cause of the abnormal APTT showed a sensitivity of 100% and specificity of 99.9%. CONCLUSION: Use of the Hepchek in the routine clinical laboratory is an efficient and rapid method of detecting heparin as a cause of isolated prolonged APTT results, and should reduce demands for unwarranted coagulation analyses and inappropriate treatment with blood products.  相似文献   
93.
Using hierarchical cluster analysis, applied to 47 cases of Guillain-Barre Syndrome (GBS) incident in South-West Stockholm (SWS) during the period from January 1973 to June 1992, we identified three major clinicoepidemiological subgroups. The first subgroup, 25.5% of the cases (26.7 ± 6.7 years), recorded a peak incidence at ages 20–29 years and presented significant differences from other subgroups, a high proportion of cases with onset at low age preceded by respiratory infection (83.3%) and with normal motor conduction velocity (50.0%). Also found, were less affected biological parameters, a rapidly progressive course and independence in gait at one month after onset. A second subgroup, 27.7% of cases, was severely affected, clinically and functionally. It consisted predominantly of young individuals (22.7 ± 11.1 years), with a high incidence (69.2% of cases) in autumn. A third subgroup, comprising 40.47; of cases, was older (61.1 ± 11.0 years) and, in general, also severely affected. The incidence of this form appeared to be invariant with time.  相似文献   
94.
95.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases.  相似文献   
96.
97.
98.
To determine the potential effect of screening on referral patterns, an adult population sample (4,404 men, 5,164 women, 20-69 years of age) was systematically recruited and screened for hypercholesterolemia and then analyzed by different cholesterol referral recommendations. Using levels suggested by the Lipid Research Clinics Coronary Primary Prevention Trial (greater than or equal to 265 mg/dL), 7.3% of men and 5.8% of women would be referred for follow-up. With the suggested recommendations of the National Cholesterol Education Program (NCEP), (greater than or equal to 200 mg/dL), 49.2% of men and 40.2% of women would be referred. The use of age-related definitions of the NIH Consensus Conference on Lipid Lowering results in 28.0% referrals in men and 21.8% in women. From this population, hypercholesterolemia subjects (greater than or equal to 265 mg/dL at screening; n = 624) were invited for a second cholesterol determination (58% returned), which found 36% below the 265 mg/dL level. Population screening for cholesterol is likely to produce large numbers of patients for follow-up, with the actual numbers strongly dependent on cutoff levels and age-sex distributions. Referral and follow-up of these patients may place a significant load on an unprepared health care community.  相似文献   
99.
100.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.  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