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   21870篇
  免费   1723篇
  国内免费   595篇
耳鼻咽喉   209篇
儿科学   344篇
妇产科学   633篇
基础医学   2925篇
口腔科学   420篇
临床医学   2364篇
内科学   4649篇
皮肤病学   277篇
神经病学   1289篇
特种医学   528篇
外国民族医学   3篇
外科学   2948篇
综合类   1512篇
现状与发展   3篇
一般理论   6篇
预防医学   1291篇
眼科学   841篇
药学   1778篇
  6篇
中国医学   604篇
肿瘤学   1558篇
  2024年   37篇
  2023年   247篇
  2022年   515篇
  2021年   772篇
  2020年   507篇
  2019年   559篇
  2018年   634篇
  2017年   555篇
  2016年   548篇
  2015年   767篇
  2014年   903篇
  2013年   1069篇
  2012年   1582篇
  2011年   1661篇
  2010年   1002篇
  2009年   806篇
  2008年   1215篇
  2007年   1248篇
  2006年   1271篇
  2005年   1252篇
  2004年   1023篇
  2003年   873篇
  2002年   855篇
  2001年   570篇
  2000年   569篇
  1999年   512篇
  1998年   206篇
  1997年   207篇
  1996年   171篇
  1995年   122篇
  1994年   119篇
  1993年   91篇
  1992年   240篇
  1991年   217篇
  1990年   185篇
  1989年   165篇
  1988年   141篇
  1987年   128篇
  1986年   106篇
  1985年   77篇
  1984年   49篇
  1983年   39篇
  1982年   57篇
  1981年   44篇
  1980年   42篇
  1979年   44篇
  1978年   42篇
  1977年   24篇
  1975年   20篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
1.
2.
“搓滚舒筋”练功疗法,是一种以竹筒为简易器械的脚底搓滚练功治疗“筋挛缩”症的方法。最早文献见于马王堆汉墓出土的帛书《五十二病方》,起码有两干多年的渊源。骨伤科常用之,内、外诸科亦有用之。这一传统疗法,筒、便、廉、验,值得弘扬。  相似文献   
3.
Transforming growth factor-β1 (TGF-β1) is known to be a potent growth inhibitor for many cell types, including most epithelial cells. In skin keratinocytes, TGF-β1 has been shown to inhibit growth and to rapidly reduce c-mycexpression. However, the molecular mechanism of TGF-β1 action on cell growth of cervical carcinoma has not yet been elucidated. We thus assessed the effect of TGF-β1 on the growth of cervical carcinoma cell lines. Two cervical squamous carcinoma cell lines, CUMC-3 and CUMC-6, were incubated with varying concentrations of TGF-β1, and growth inhibition was evaluated with tetrazolium-based colorimetric assay. After culture in TGF-β1 for 24 h, inhibition of growth was detected in a dose-dependent manner at concentrations of 0.1–10 ng/ml in both cell lines. This effect of TGF-β1 on cultured carcinoma cells was associated with apoptotic process including oligonucleosomal ladder DNA and apoptotic body formations. Northern blot analysis revealed c-mycmRNA expression was suppressed by 10 ng/ml of TGF-β1 following 3 h of treatment in both cell lines. Western blot analysis showed that the level of p27Kip1protein was increased after TGF-β1 treatment in both cell lines. These results suggest that the mechanisms by which TGF-β1 inhibits the growth of cervical carcinoma are complex and may include effects on down-regulation of c-mycgene, and overexpression of p27Kip1protein.  相似文献   
4.
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996  相似文献   
5.
6.
The purpose of this study is to develop an evaluation instrument with high feasibility and acceptability, and to quantify the outcome of evaluation, in order to set up an efficient evaluation system. Teaching evaluation with questionnaire by students has been carried out in National Yang-Ming Medical College for two years. With the support of both teachers and students, the system has been established and conducted on a regular basis. The most important purpose of evaluation is to improve the quality of teaching. During the two academic years (Sep. 1986-June 1988) of the program, the overall response rate was 44.5%, the Department of Nursing had the highest response rate, followed by Dentistry, Medicine-Post Graduate, Medical Technology, and Medicine. Taking into consideration of the year and the class size, the regression analysis found that higher year or smaller size of the class had better response rate. The response rates dropped significantly after the first academic year regardless of department or year. A total of 23 classes were included in the evaluation program and 99 courses were evaluated. All questions in the questionnaire used a 0 to 4 ordinal scale, in which 0 (improvement needed) was the low end and 4 (excellent) the high end. The mean score of the seven questions of teaching evaluation was 2.47. As a whole, the students were satisfied with the teaching. As to the categories of courses, clinical courses had better mean score than basic medical courses, and basic medical courses had better mean score than common required courses. To evaluate the effectiveness of the teaching, students' achievement was used as the outcome variable. The most important predictive variable was the method of instruction, followed by the content of lecture such as degree of difficulty of the lecture and cognitiveness of the contents. The above 3 variables explained 76% of the variation of the students' achievement. However, the significant of teachers' speech, performance and attitude were not so influential. Analysis based on the characteristics of the teachers (sex, age, position, and teaching experience), the characteristics of students (department and year), teaching environments (time and place), and the 3 categories of courses (clinical, basic medical and common required courses) showed that all the above variables only explained less then 10% of the variation of the students' achievement.  相似文献   
7.
Fifty patients, 21 with transposition of the great arteries plus ventricular septal defect, four with double-outlet right ventricle plus ventricular septal defect, and 25 with transposition of the great arteries plus intact ventricular septum, have undergone anatomic correction. There were four hospital deaths, all in the patients with ventricular septal defects (overall mortality rate 8%). The Lecompte maneuver was used in all patients, and in the last 25 patients the coronary arteries were transposed to medially hinged trapdoor flaps created in the neoaorta. In 10 patients (20%) intraoperative adjustments were necessary to the great vessels and coronary arteries to achieve unobstructed coronary artery flow. There have been no late deaths. Postoperative cardiac catheterization in 19 patients has revealed stenosis on the new main pulmonary artery suture line to be the main early problem. Anatomic correction of transposition (with or without ventricular septal defect) and double-outlet right ventricle septal defect would seem to be a good operative alternative to the Mustard or Senning operation, with the advantage of incorporating the left ventricle into the systemic circulation.  相似文献   
8.
重症肌无力病人乙酰胆碱受体抗体的测定及临床意义   总被引:7,自引:0,他引:7  
用ELISA(固相酶联免疫吸附)法测定172例MG病人血清乙酰胆碱受体抗体(AchRab),结果显著高于健康献血员组和非MG病人组。不同性别、病程及临床类型与AchRab无相关性,但41~50岁组的显著高于其他年龄组。67例类固醇激素治疗组、22例大剂量两种球蛋白治疗组、12例胸腺切除术组及3例MG危象病人24次血浆交换疗法(PE)组,治疗后伴随肌无力症状的好转,AchRab均显著低于治疗前。结果表明:AchRab测定为MG诊断提供了可靠的实验依据,为类固醇激素、大剂量丙种球蛋白、胸腺切除术和PE等治疗MG提供理论依据和疗效评定的实验指标,进一步证实了MG免疫学发病机理。  相似文献   
9.
We present two case studies, one of generalized chorea and one of hemichorea, both after severe hypoglycemia episodes. Both cases showed hyperperfusion in their SPECT scans. The MRI and SPECT findings serve as clues regarding the role of basal ganglion dysfunction associated with chorea.  相似文献   
10.
To better understand the impact of incident Parkinson's disease (PD) on the Veteran's Health Administration (VHA) and to develop methods applicable to future epidemiological research, we performed a medical record review study at a tertiary referral VHA medical center. Searching the local data base, we identified 782 veterans with diagnostic codes for PD or secondary parkinsonism (SP) between 1998 and 2000. Based on structured medical record review, a movement disorders specialist confirmed diagnoses for incident parkinsonism cases. Among the 782, 191 incident parkinsonism cases were identified (100 PD, 75 SP, and 16 Parkinson's Plus). Incident PD cases were older at diagnosis (74.5 vs. 70.4 yr; P < 0.05) and more likely to be white (81% vs. 62; P < 0.07) than incident SP cases. Diagnostic codes were insufficient to distinguish between incident PD and SP (positive predictive value, 57% and 39%, respectively), and VHA sources failed to identify 21% of confirmed deaths among the incident PD cohort by November 2004. Although the large number of incident cases identified suggests PD is an important cause of disability among elderly VHA users, observed limitations of VHA sources for identifying incident PD cases and determining their vital status should be considered when designing future studies.  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