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   55708篇
  免费   4846篇
  国内免费   1514篇
耳鼻咽喉   543篇
儿科学   1338篇
妇产科学   1140篇
基础医学   6639篇
口腔科学   964篇
临床医学   5906篇
内科学   10783篇
皮肤病学   1157篇
神经病学   3501篇
特种医学   2018篇
外国民族医学   5篇
外科学   7278篇
综合类   4625篇
现状与发展   5篇
一般理论   36篇
预防医学   3579篇
眼科学   1904篇
药学   4869篇
  10篇
中国医学   1375篇
肿瘤学   4393篇
  2024年   79篇
  2023年   464篇
  2022年   957篇
  2021年   1591篇
  2020年   1166篇
  2019年   1384篇
  2018年   1668篇
  2017年   1353篇
  2016年   1590篇
  2015年   1937篇
  2014年   2461篇
  2013年   2866篇
  2012年   3892篇
  2011年   4102篇
  2010年   2686篇
  2009年   2394篇
  2008年   3092篇
  2007年   3179篇
  2006年   3085篇
  2005年   2878篇
  2004年   2703篇
  2003年   2670篇
  2002年   2376篇
  2001年   1834篇
  2000年   1513篇
  1999年   1207篇
  1998年   506篇
  1997年   429篇
  1996年   342篇
  1995年   260篇
  1994年   267篇
  1993年   223篇
  1992年   500篇
  1991年   492篇
  1990年   458篇
  1989年   435篇
  1988年   370篇
  1987年   400篇
  1986年   343篇
  1985年   284篇
  1984年   220篇
  1983年   157篇
  1982年   105篇
  1981年   93篇
  1980年   96篇
  1979年   151篇
  1978年   96篇
  1977年   82篇
  1976年   80篇
  1975年   85篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Studies of the ontogeny of IGF-I mRNA during embryonic and larval development of the gilthead sea breamSparus auratashowed its expression during these early developmental stages. The present study appliesin situhybridization to localize IGF-I and IGF receptor mRNAs in 16-day larvae ofS. aurata.Paraffin sections were hybridized with homologous RNA probes labeled by [35S]UTP. IGF-I mRNA expression was found mainly in chondrocytes, in both the gill arches and cranial cartilage, in skeletal muscle, in the brain, in the pancreas, in the retina, and in the epithelial cells surrounding the lens. A strong positive reaction for IGF receptor mRNA was found in skeletal muscle, in the pancreas, and in the lymphoid tissue found in the intertubular tissue of the kidney. Signals were less intense in brain and chondrocytes. It is suggested that in teleosts, as in higher vertebrates, IGF-I may be involved in the regulation of tissue growth and differentiation in an autocrine/paracrine manner.  相似文献   
22.
23.
Laparoscopic appendicectomy has been the subject of several encouraging reports, but has not as yet gained widespread acceptance. We present a series of 159 consecutive laparoscopic appendicectomies performed, over a 4 yr period, in both adults and children. We find the procedure as safe as its open counterpart, with patients fit to leave hospital within the same time period. Perforated appendices were amenable to this procedure, and the location of the appendix did not alter the outcome. Children responded as well as adults post-operatively. Obesity may be an indication for this form of treatment. Removal of displaced faecoliths associated with perforated appendicitis is a difficult technical problem in less than 5 per cent of patients.  相似文献   
24.
Summary We have completed a phase I and pharmacology study of liposomally-encapsulated daunorubicin (DaunoXome). Of 32 patients entered, 30 were evaluable. No toxicity was encountered at the initial doseescalation steps from 10 to 60 mg/m2. At 80 mg/m2, two patients manifested grade 2 neutropenia. At least grade 3 neutropenia occurred in all patients receiving 120 mg/m2. Alopecia and subjective intolerance were mild. Cardiotoxicity was not observed except for an episode of arrhythmia in a patient with lung cancer and prior radiation. Only one minor objective response was observed in this population of refractory solid tumors. Pharmacokinetics differed from those of the free drug with no detection of daunorubicinol. We recommend future phase II studies with a dose of 100 mg/m2 in previously treated and 120 mg/m2 of DaunoXome in previously untreated patients with solid tumors.EDW is supported in part by ACS award 92-14-1  相似文献   
25.
26.
We identified 18 patients with double-orifice mitral valve (DOMV) and intact atrioventricular (AV) septum out of 40,179 echocardiographic studies performed between 1997 and 2002 at Children's Hospital, Denver, CO. In this study we describe (1) the anatomic characteristics of the DOMV in the absence of AV septal defect, (2) the function of the mitral valve by spectral and color Doppler flow mapping, and (3) associated lesions. The topographic location of the orifices in the leaflets suggests possible embryologic mechanisms of DOMV. In this series, DOMV was most commonly associated with left-sided obstructive lesions (in 39% of patients). Spectral and color Doppler interrogation demonstrated a normal flow profile in most cases; only 2 patients had significant mitral regurgitation or stenosis. Therefore, due to the uncertain natural history of this lesion and the potential need for endocarditis prophylaxis, careful imaging of the mitral valve is recommended, particularly in the presence of left-sided obstructive lesions.  相似文献   
27.
This study examines how acute hand injuries affect patients in their roles as spouse, caregiver, and/or worker. Qualitative data from patient interviews were used to analyze how these life roles were affected by the individuals' hand injuries. Data were extracted from interviews of three hand patients who had one or more roles of spouse, caregiver, and/or worker affected by their injury. Data were then examined and categorized for each life role by participant. Participants' views of how hand therapy affected their recovery and resumption of occupational role performance were also examined. Results showed that the participants expressed profound degrees of change in their ability to perform satisfactorily in their various life roles.  相似文献   
28.
通过检测对激素不同反应、不同病情的肾病综合征(NS)患者的血清及淋巴细胞内腺苷脱氨酶(ADA)的活性变化,观察ADA活性与临床疗效的关系。  相似文献   
29.
BACKGROUND: Increased autoantibody prevalence has been described in instances of high-dose exposure to polychlorinated biphenyls (PCBs). In 1996, an equipment malfunction at the Swan Hills Treatment Centre in Alberta, Canada, caused the release of gases containing PCBs into the ambient air. In view of the immune effects of PCBs and their potential as endocrine disruptors, we assessed autoantibody prevalence and looked for correlations with PCB levels. METHODS: Fifty-seven persons living within a 100 km radius of the waste treatment facility were assessed. Autoantibodies were measured by indirect immunofluorescence, double immunodiffusion, and immunoblotting. The levels of 26 congeners of PCBs were measured by gas chromatography and mass spectrometry. Provincial health records for physician visits and hospitalizations were reviewed for diagnoses of autoimmune disease. RESULTS: The prevalence of autoantibodies was 11% in the study participants and 0% in healthy controls. There was no correlation of PCB levels with autoantibody results. There was no associated increase in autoimmune disease noted on physician visits or hospitalizations. PCB levels were comparable to background levels reported for other populations. CONCLUSION: A correlation of titers of autoantibodies in the sera of individuals at risk and the blood levels of PCBs was not found, and the prevalence of autoantibodies in the at-risk group was not statistically different (p > .05) from that of an unexposed control group. The study group had higher titers of autoantibodies and some strong reactivity with intracellular antigens, but the significance of this observation may be understood only after long-term clinical assessments and follow-up.  相似文献   
30.
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