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   762篇
  免费   51篇
  国内免费   26篇
儿科学   58篇
妇产科学   9篇
基础医学   61篇
口腔科学   37篇
临床医学   64篇
内科学   150篇
皮肤病学   9篇
神经病学   111篇
特种医学   119篇
外国民族医学   1篇
外科学   33篇
综合类   7篇
预防医学   58篇
眼科学   7篇
药学   90篇
肿瘤学   25篇
  2022年   4篇
  2021年   4篇
  2020年   5篇
  2019年   4篇
  2018年   8篇
  2017年   4篇
  2016年   6篇
  2015年   7篇
  2014年   10篇
  2013年   17篇
  2012年   30篇
  2011年   16篇
  2010年   15篇
  2009年   30篇
  2008年   20篇
  2007年   38篇
  2006年   27篇
  2005年   22篇
  2004年   12篇
  2003年   23篇
  2002年   15篇
  2001年   28篇
  2000年   16篇
  1999年   18篇
  1998年   41篇
  1997年   45篇
  1996年   52篇
  1995年   40篇
  1994年   32篇
  1993年   32篇
  1992年   14篇
  1991年   12篇
  1990年   12篇
  1989年   22篇
  1988年   19篇
  1987年   18篇
  1986年   15篇
  1985年   13篇
  1984年   12篇
  1983年   10篇
  1982年   7篇
  1981年   5篇
  1980年   6篇
  1979年   5篇
  1977年   8篇
  1976年   8篇
  1975年   9篇
  1974年   4篇
  1973年   4篇
  1968年   3篇
排序方式: 共有839条查询结果,搜索用时 15 毫秒
1.
ObjectiveWe examine remission rate probabilities, recovery rates, and residual symptoms across 36 weeks in the Treatment for Adolescents with Depression Study (TADS).MethodThe TADS, a multisite clinical trial, randomized 439 adolescents with major depressive disorder to 12 weeks of treatment with fluoxetine, cognitive–behavioral therapy, their combination, or pill placebo. The pill placebo group, treated openly after week 12, was not included in the subsequent analyses. Treatment differences in remission rates and probabilities of remission over time are compared. Recovery rates in remitters at weeks 12 (acute phase remitters) and 18 (continuation phase remitters) are summarized. We also examined whether residual symptoms at the end of 12 weeks of acute treatment predicted later remission.ResultsAt week 36, the estimated remission rates for intention-to-treat cases were as follows: combination, 60%; fluoxetine, 55%; cognitive–behavioral therapy, 64%; and overall, 60%. Paired comparisons reveal that, at week 24, all active treatments converge on remission outcomes. The recovery rate at week 36 was 65% for acute phase remitters and 71% for continuation phase remitters, with no significant between-treatment differences in recovery rates. Residual symptoms at the end of acute treatment predicted failure to achieve remission at weeks 18 and 36.ConclusionsMost depressed adolescents in all three treatment modalities achieved remission at the end of 9 months of treatment.  相似文献   
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.
Infections in British clinical laboratories, 1988-1989.   总被引:6,自引:3,他引:3       下载免费PDF全文
During 1988-89 this continuing survey showed 18 infections in the staff of laboratories reporting from 166 centres, representing 21,756 person-years of exposure. Shigella and other bowel infections (one caused by S typhi) predominated, affecting 11 microbiology medical laboratory scientific officers. Three shigella infections originated from quality control samples. Pulmonary tuberculosis affected four workers, including two mortuary technicians, but without detected occupational exposure to Mycobacterium tuberculosis. Other infections included one caused by Brucella melitensis. Hepatitis was not reported. The sustained low level of hepatitis is encouraging and suggests a low risk to staff of bloodborne infections such as human immunodeficiency virus.  相似文献   
5.
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   
6.
约有6%~20%的儿童和青少年患有广泛性焦虑、分离性焦虑和社交恐惧症,但是临床医生对于儿童和青少年的精神障碍认识尚不充分.这一问题非常严重,因为如果发病年龄小、病情较重,那么患者成人之后的结局往往很差.此外,如果不能早期诊断,焦虑症、抑郁症和药物滥用的发生率就会增加.在最近的<新英格兰医学杂志>中,发表了由Walkup等人进行的有关儿童-青少年焦虑症的多模型研究(CAMS)的结果,该项研究对上述精神障碍早期治疗的必要性进行了论述.  相似文献   
7.
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   
8.
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   
9.
Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.   相似文献   
10.
We have recently shown using dansyl-L-lysine exclusion studies that the release of human chorionic gonadotrophin (HCG) in conjunction with L- lactate dehydrogenase (LDH) from first trimester villi during organ culture is symptomatic of syncytiotrophoblast degeneration. The purpose of this study was to examine chorionic villi at the ultrastructural level in order to determine events occurring during organ culture. The tissue was sampled after 0, 24, 48 and 120 h in culture and processed for electron microscopy. In addition to confirming the previously recorded syncytial degeneration, the electron micrographs showed clearly the generation of a new syncytiotrophoblast layer. The new layer, derived from differentiating cytotrophoblast cells, was largely formed by 48 h and was maintained for at least 120 h in culture. This study demonstrates a model which provides an opportunity to study the differentiation of cytotrophoblast cells whilst they retain their anatomical relationships within the villous structure.   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