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   2159篇
  免费   105篇
  国内免费   37篇
耳鼻咽喉   14篇
儿科学   126篇
妇产科学   48篇
基础医学   262篇
口腔科学   47篇
临床医学   283篇
内科学   411篇
皮肤病学   19篇
神经病学   113篇
特种医学   173篇
外科学   169篇
综合类   27篇
预防医学   246篇
眼科学   45篇
药学   213篇
中国医学   7篇
肿瘤学   98篇
  2023年   5篇
  2022年   21篇
  2021年   43篇
  2020年   24篇
  2019年   24篇
  2018年   42篇
  2017年   27篇
  2016年   36篇
  2015年   53篇
  2014年   52篇
  2013年   90篇
  2012年   142篇
  2011年   140篇
  2010年   72篇
  2009年   62篇
  2008年   120篇
  2007年   138篇
  2006年   124篇
  2005年   133篇
  2004年   118篇
  2003年   101篇
  2002年   109篇
  2001年   23篇
  2000年   20篇
  1999年   17篇
  1998年   51篇
  1997年   60篇
  1996年   60篇
  1995年   48篇
  1994年   34篇
  1993年   38篇
  1992年   18篇
  1991年   13篇
  1990年   15篇
  1989年   26篇
  1988年   26篇
  1987年   15篇
  1986年   15篇
  1985年   14篇
  1984年   19篇
  1983年   12篇
  1982年   12篇
  1981年   19篇
  1980年   8篇
  1979年   6篇
  1978年   7篇
  1977年   6篇
  1976年   7篇
  1975年   14篇
  1974年   4篇
排序方式: 共有2301条查询结果,搜索用时 515 毫秒
1.
2.
3.
de Vries Reilingh  TS  van Geldere  D  Langenhorst  BLAM  de Jong  D  van der Wilt  GJ  van Goor  H  Bleichrodt  RP 《Hernia》2004,8(1):56-59
Polypropylene mesh is widely used for the reconstruction of incisional hernias that cannot be closed primarily. Several techniques have been advocated to implant the mesh. The objective of this study was to evaluate, retrospectively, early and late results of three different techniques, onlay, inlay, and underlay. The records of 53 consecutive patients with a large midline incisional hernia — 25 women and 28 men, mean age 60.4 (range 28–94) — were reviewed. Polypropylene mesh was implanted using the onlay technique in 13 patients, inlay in 23 patients, and underlay in 17 patients. Either the greater omentum or a polyglactin mesh was interponated between the mesh and the viscera. The records of these 53 patients were reviewed with respect to: size and cause of the hernia, pre- and postoperative mortality and morbidity, with special attention to wound complications. Patients were invited to attend the outpatient clinic at least 12 months after implantation of the mesh for physical examination of the abdominal wall. Postoperative complications occurred in 14 (26.4%) patients. The onlay technique had significantly more complications, as compared to both other techniques. Reherniation occurred in 15 (28.3%) patients. The reherniation rate of the inlay technique was significantly higher than after the underlay technique (44% vs 12%, P=0.03) and tended to be higher than the onlay technique (44% vs 23%, P=0.22). Repair of large midline incisional hernias with the use of a polypropylene mesh carries a high risk of complications and has a high reherniation rate. The underlay technique seems to be the better technique.  相似文献   
4.
OBJECTIVE: Restraint use is not monitored in the US, and only institutions that choose to do so collect statistics. In 1999, investigative journalists reported lethal consequences proximal to restraint use, making it a life-and-death matter that demands attention from professionals. This paper reviews the literature concerning actual and potential causes of deaths proximal to the use of physical restraint. METHOD: Searching the electronic databases Medline, Cinahl, and PsycINFO, we reviewed the areas of forensics and pathology, nursing, cardiology, immunology, psychology, neurosciences, psychiatry, emergency medicine, and sports medicine. CONCLUSIONS: Research is needed to provide clinicians with data on the risk factors and adverse effects associated with restraint use, as well as data on procedures that will lead to reduced use. Research is needed to determine what individual risk factors and combinations thereof contribute to injury and death.  相似文献   
5.
6.
To conduct a formative and pilot impact evaluation of the State Technical Assessment Team (STAT) program, a visitation-based (visitatie) peer assessment program designed to enhance the organizational capacity of state health department injury prevention programs. The formative evaluation was based on observational, record review, and key informant interview data collected during the implementation of the first 7 STAT visits. Pilot impact data were derived from semi-structured interviews with state injury prevention personnel one year after the visit. Formative evaluation identified 6 significant implementation problems in the first visits that were addressed by the program planners, resulting in improvements to the STAT assessment protocol. Impact evaluation revealed that after one year, the 7 state injury prevention programs had acted on 81% of the recommendations received during their STAT visits. All programs reported gains in visibility and credibility within the state health department and increased collaboration and cooperation with other units and agencies. Other significant program advancements were also reported. Specific program standards and review procedures are important to the success of peer assessment programs such as STAT. Early impact evaluation suggests that peer assessment protocols using the visitatie model can lead to gains in organizational capacity.  相似文献   
7.
Olson  MA; Becker  GJ 《Radiology》1986,159(1):25-26
An anomalous pulmonary vein draining into the subdiaphragmatic inferior vena cava was initially demonstrated on computed tomographic (CT) scans. The diagnosis of scimitar syndrome was confirmed with digital subtraction angiography. In retrospect, the anomalous vein and dextroposition of the heart were shown on chest radiographs.  相似文献   
8.
One-hundred and six male children aged 6-23 months with a history of acute watery diarrhoea of less than 72 h duration were randomized to receive either folic acid in a dose of 5 mg at 8-h intervals or placebo for 5 d. There were 54 children in the folic acid group and 52 in the placebo group. The admission characteristics were comparable between the two groups. No significant differences were observed in the intake of oral rehydration solution or stool output between the groups. The mean ± SD of total stool output (g kg−1) was 532 ± 476 vs 479 ± 354 and the duration (h) of diarrhoea was 108 ± 68 vs 103 ± 53 in the folic acid vs placebo group, respectively. The findings, therefore, should have a positive influence on preventing the inappropriate use of folic acid in acute diarrhoea.  相似文献   
9.
Gramzinski  RA; Broze  GJ Jr; Carson  SD 《Blood》1989,73(4):983-989
Studies of proteins that inhibit tissue factor activity have generally been conducted using either an extracted tissue homogenate ("thromboplastin") or tissue factor protein reconstituted into phospholipid vesicles rather than with tissue factor expressed in cell membranes (its physiological environment). In the present study, a human fibroblast cell strain was used to evaluate the effects of lipoprotein associated coagulation inhibitor (LACI), placental anticoagulant protein (PAP), and apolipoprotein A-II (apo A-II) on human tissue factor in cell membranes. LACI was tested from 7.8 to 500 pmol/L on fibroblasts cultured at cell densities ranging from 3,500 to 9,925 cells/well, and caused a progressive inhibition of tissue factor activity. PAP was tested from 3.9 nmol/L to 1 mumol/L at cell densities ranging from 4,500 to 15,400 cells/well and caused up to 83% inhibition of tissue factor activity. Inhibition by these proteins appeared to be influenced by cell density as well as whether the cells were intact or disrupted. Apo A-II, up to 1 mumol/L, did not inhibit the tissue factor activity of intact or disrupted fibroblasts at any cell density examined even though it did inhibit the activity of tissue factor in phospholipid vesicles. Of these inhibitors of tissue factor-dependent activation of factor X, LACI was the most effective in suppressing the generation of factor Xa activity. The effects obtained with apo A-II are clearly dependent on the nature of the tissue factor preparation with which it is tested. The disparity between the inhibitory effect of apo A-II on the activity of tissue factor reconstituted into lipid vesicles and the absence of effect on the activity of tissue factor remaining in cell membranes serves to reemphasize the necessity of reexamining results obtained with model systems using as nearly physiological reagents as possible.  相似文献   
10.
Superoxide dismutase (SOD) content estimated by rocket immunoelectrophoresis did not differ in various density (age) fractions of bovine erythrocytes though its specific activity decreased with increasing cell density. No changes were found, either, in the crossed immunoelectrophoretic pattern of SOD with increasing red cell age. Effects of different denaturing agents on the immunoelectrophoretic pattern and activity of the enzyme were compared, including H2O2 and free radicals generated by ionizing radiation. The yield for inactivation was higher than that for loss of antigenic properties in all cases studied which could correspond to the in vivo situation. However, changes in electro-phoretic mobility were revealed for all the denaturing agents, which is contrary to a main causative role of these agents in the in vivo inactivation of SOD. The results suggest spontaneous “subtle denaturation” as a chief cause for the SOD inactivation during erythrocyte aging.  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