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   102276篇
  免费   7766篇
  国内免费   376篇
耳鼻咽喉   1128篇
儿科学   2533篇
妇产科学   1649篇
基础医学   14481篇
口腔科学   2193篇
临床医学   10467篇
内科学   21728篇
皮肤病学   1796篇
神经病学   10914篇
特种医学   4215篇
外国民族医学   6篇
外科学   14626篇
综合类   1251篇
一般理论   73篇
预防医学   7925篇
眼科学   1732篇
药学   6913篇
中国医学   111篇
肿瘤学   6677篇
  2023年   573篇
  2022年   1085篇
  2021年   2142篇
  2020年   1319篇
  2019年   1971篇
  2018年   2424篇
  2017年   1786篇
  2016年   2133篇
  2015年   2478篇
  2014年   3266篇
  2013年   4298篇
  2012年   6654篇
  2011年   6714篇
  2010年   3962篇
  2009年   3611篇
  2008年   5927篇
  2007年   6429篇
  2006年   5954篇
  2005年   5902篇
  2004年   5508篇
  2003年   4916篇
  2002年   4873篇
  2001年   1867篇
  2000年   1782篇
  1999年   1658篇
  1998年   1216篇
  1997年   997篇
  1996年   807篇
  1995年   816篇
  1994年   695篇
  1993年   635篇
  1992年   1151篇
  1991年   1067篇
  1990年   1010篇
  1989年   971篇
  1988年   863篇
  1987年   810篇
  1986年   833篇
  1985年   827篇
  1984年   670篇
  1983年   578篇
  1982年   554篇
  1981年   453篇
  1980年   394篇
  1979年   515篇
  1978年   406篇
  1977年   368篇
  1975年   327篇
  1974年   356篇
  1973年   343篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
The loss of available iodine from povidone-iodine solution stored in contact with two different polyetherpolyurethane foams was monitored as a function of time and temperature. Statistical evaluation of the results for the four temperatures studied [ambient (25 degrees), 30, 45 and 55 degrees C] indicated the chemical equivalence of the two foams as storage and delivery systems for povidone-iodine solution in terms of solution stability. In addition, application of a first-order kinetic model to the data produced an acceptable fit. An Arrhenius-type evaluation of the resulting rate constants yielded a linear relationship which was shown to be useful for predicting loss of available iodine under ambient temperature conditions of storage.  相似文献   
132.
133.
Objective: The aim of this study was to determine the prevalence of low back pain (LBP) in a primary care setting population and examine its association with the symptoms of depression and somatization. Methods: This is a cross‐sectional study, utilising a survey carried out in primary health care clinics (PHCs) in Al‐Ain, United Arab Emirates (UAE). A multistage stratified sampling design was used and a representative sample of 1304 UAE nationals aged 18–65 years who attended PHC clinics for any reason were included and 1103 (84.5%) subjects agreed to participate and responded to the questionnaire during a period from June 2001 to January 2002. A specially designed questionnaire with three parts was used for the data collection: socio‐demographic information of the studied subjects, modified version of the Roland‐Morris scale for evaluating back‐related functional disability and SCL‐90 R for depression and somatization subscales was used to assess depressive and somatic symptoms. Results: Of the total number of subjects surveyed (1103), 586 (53.1%) were men and 517 (46.9%) women. The mean age was 34.9 ± 13.4 years for men and 33.5 ± 11.8 years for women. The prevalence of LBP in the studied subjects was 64.7% (95% CI, 60.7–68.5] with 46.7% among men and 53.3% among women. There were a significant differences between the subjects with LBP and without LBP with respect to gender (P < 0.001), body mass index (BMI) (P < 0.001), occupational status (P < 0.001) and living environment (P = 0.016). Functional disability was higher in patients with LBP. Young patients in aged 15–34 years, patients with preparatory/secondary educational level and students showed higher depressive symptoms. A similar pattern was found in patients with somatic symptoms. Factor analysis revealed a strong association between depression and somatization in LBP patients. Conclusions: Functional disability was higher in with LBP. Furthermore, symptoms of depression and somatization are prevalent among LBP patients.  相似文献   
134.
Abstract: We describe the use of restriction analysis on PCR-amplified DNA for detecting all B*27 subtypes except B*2710 and B*2711 (i.e. from B*2701 to B*2709). After detecting B*27 by Sty I, double digestions consisting of Sty I plus another informative enzyme led to subtype assignment. We used mismatched primers to create restriction sites when necessary. The method avoids group-specific amplifications and other laborious optimization procedures. It was successfully tested on a panel of well characterized cell lines covering different B*27 subtypes. Then, we studied a group of 57 ankylosing spondyiitis patients and 746 controls from the south of Spain. B*27 showed a very strong association with the disease (OR=211.27, P=\0˜7). B*2702 and B*2705 distribution in controls (20% and 77.1%, respectively) differed from previously reported data in the Spanish population. We unexpectedly found the B*2707 allele in our population (one control).  相似文献   
135.
Bony fusions involving the carpus have a much higher prevalence in blacks relative to whites. This article describes a case of lunotriquetral coalition fracture-dislocation in an African American. This lesion is best treated through open reduction and pin fixation.  相似文献   
136.
The anticancer agent temozolomide labeled with 13C (8-Carbamoyl-3-13C-methylimidazo-[5,1-d]-1,2,3,5-tetrazin-4-(3H)-one), was noninvasively detected in subcutaneous RIF-1 tumors by a selective cross polarization 13C NMR method, at a field strength of 9.4T. Pharmacokinetics of the drug, at a dose of 150 mg/kg, were determined for intravenous and intraperitoneal modes of administration (three animals per mode). The half-life of the drug in the tumors was approximately 60 min. The uptake and clearance of the drug, however, varied significantly between individual hosts, for both modes of administration. These results demonstrate the feasibility of obtaining pharmacokinetics of anticancer agents for individual tumors without the need for a label that might modify drug activity (e.g., fluorine). The variability of the in vivo measurements, even within the same tumor model, demonstrates the necessity of directly monitoring the tumor to evaluate drug pharmacokinetics.  相似文献   
137.
138.
The ability of the calcium entry blocker verapamil to ameliorate the effects of renal ischemia was studied in ten sheep. Postanesthesia, bilateral cutaneous ureterostomies were placed in each sheep to facilitate urine collection and analysis. Both kidneys were made ischemic for one hour by occluding each renal artery. However, immediately before occlusion of the right renal artery, 0.05 mg/kg of verapamil was injected into the artery. Comparison of urinary creatinine excretion and urine volume for 72 h after reversal of ischemia demonstrated that those kidneys pretreated with verapamil had greater functional preservation (p less than .05). In this study, verapamil appeared to provide protection against renal damage after an ischemic insult.  相似文献   
139.
In child and youth care in the Netherlands, systematic planning of treatment is more and more considered to be a condition for effective and well founded treatment. Although workers are convinced of the benefits of treatment plans, treatment planning is not yet a natural and integrated part of residential care. There are several pressure points. In this article a model of treatment planning will be presented that contributes to an answer to these pressure points. The theoretical bases and the practical implications of this model will be discussed.  相似文献   
140.
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