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   2275篇
  免费   155篇
  国内免费   7篇
耳鼻咽喉   15篇
儿科学   88篇
妇产科学   119篇
基础医学   332篇
口腔科学   102篇
临床医学   233篇
内科学   435篇
皮肤病学   40篇
神经病学   327篇
特种医学   126篇
外科学   165篇
综合类   13篇
预防医学   115篇
眼科学   9篇
药学   212篇
中国医学   1篇
肿瘤学   105篇
  2023年   12篇
  2022年   24篇
  2021年   51篇
  2020年   22篇
  2019年   32篇
  2018年   55篇
  2017年   40篇
  2016年   38篇
  2015年   43篇
  2014年   64篇
  2013年   66篇
  2012年   137篇
  2011年   117篇
  2010年   63篇
  2009年   57篇
  2008年   99篇
  2007年   89篇
  2006年   92篇
  2005年   90篇
  2004年   85篇
  2003年   76篇
  2002年   93篇
  2001年   60篇
  2000年   78篇
  1999年   71篇
  1998年   27篇
  1997年   19篇
  1996年   24篇
  1995年   22篇
  1994年   21篇
  1993年   17篇
  1992年   69篇
  1991年   69篇
  1990年   54篇
  1989年   50篇
  1988年   42篇
  1987年   32篇
  1986年   29篇
  1985年   29篇
  1984年   17篇
  1983年   17篇
  1982年   22篇
  1981年   17篇
  1979年   14篇
  1978年   19篇
  1975年   15篇
  1974年   15篇
  1973年   15篇
  1967年   12篇
  1966年   11篇
排序方式: 共有2437条查询结果,搜索用时 375 毫秒
101.
102.
We investigated if the MET-activating point mutation Y1253D influences clinical outcomes in patients with advanced squamous cell carcinoma of the head and neck (HNSCC). The study population consisted of 152 HNSCC patients treated by hyperfractionated radiotherapy alone or concomitant with chemotherapy between September 1994 and July 2000. Tumors were screened for the presence of the MET-activating point mutation Y1253D. Seventy-eight patients (51%) received radiotherapy alone, 74 patients (49%) underwent radiotherapy concomitant with chemotherapy. Median patient age was 54 years and median follow-up was 5.5 years. Distant metastasis-free survival, local relapse-free survival and overall survival were compared with MET Y1253D status. During follow-up, 29 (19%) patients developed distant metastasis. MET Y1253D was detected in tumors of 21 out of 152 patients (14%). Distant metastasis-free survival (P = 0.008) was associated with MET Y1253D. In a multivariate Cox regression model, adjusted for T-category, only presence of MET Y1253D was associated with decreased distant metastasis-free survival: hazard ratio = 2.5 (95% confidence interval: 1.1, 5.8). The observed association between MET Y1253D-activating point mutation and decreased distant metastasis-free survival in advanced HNSCC suggests that MET may be a potential target for specific treatment interventions.  相似文献   
103.
The lack of endogenous insulin secretion in type 1 diabetes can cause dangerous hypo- and hyperglycemia during exercise in patients with type 1 diabetes. However, because of the increasing prevalence of obesity and lifestyle diseases, the beneficial effects of regular exercise clearly outweigh the dangers of exercising with type 1 diabetes. However, intensified training/education on metabolic regulation during exercise is necessary from the perspective of preventative medicine to be able to benefit fully from its effects.  相似文献   
104.
The identification of tumor initiating cells or tumor stem cells capable of self-renewal has changed our fundamental view on tumorigenesis and tumor progression. A hierarchical order of different aggressive cell types derived from a small population of brain tumor stem cells is the basis for the heterogeneity in malignant gliomas. The glioma stem cells are extremely resistant to chemotherapy and radiotherapy they survive adjuvant cancer therapy and are the basis for recurrent tumor growth and clinical relapse. Therefore, modern therapies should be targeted against this cell type. It is a major goal to identify brain tumor stem cell markers for imaging and to enhance neuropathological diagnostics.  相似文献   
105.
106.
107.
A cross-sectional transvaginal ultrasound study was conducted in 137 normal pregnancies with gestational ages ranging from 5-12 weeks. Several biometric measurements were obtained throughout pregnancy, including the three diameters of the gestational sac, the crown-rump length, and the yolk sac. In addition, the appearance of the embryo heartbeat and embryo body movements were evaluated. Linear relationships were found between the mean gestational sac diameters and gestational age (r = 0.911; P less than .00001) and between mean gestational sac growth and crown-rump length growth (r = 0.926; P less than .0001). A gestational sac could be identified at 5 weeks' gestation; embryo heartbeat was imaged when the mean gestational sac diameter measured 2 cm, and embryo body movements could be seen when the mean gestational sac diameter reached 3 cm. In the present study, embryo heartbeat was identifiable after 6 weeks and 4 days with a sensitivity of 100%, specificity of 93.1%, positive predictive value of 96.9%, and negative predictive value of 100%. The embryo body movements, which were absent before 7 weeks' gestation, were observed after 8 weeks' gestation with a sensitivity of 100%, specificity of 92.8%, positive predictive value of 94.3%, and negative predictive value of 100%. With identification by transvaginal sonographic evaluation, the following can serve as markers of normal embryo growth: a mean gestational sac diameter greater than 2 cm in the presence of the embryo heartbeat, or a mean sac diameter measurement greater than 3 cm in the presence of embryo movement.  相似文献   
108.
109.
In a prospective, randomized trial, the efficacy of a single-dose, first-generation, long-acting cephalosporin was compared with a three-dose regimen in a group of 100 women undergoing cesarean section who were at high risk for postoperative febrile morbidity. Fifty women received a single 1 gm intravenous dose of cefazolin and 50 received 1 gm of the drug followed by two additional doses, 8 hours apart, to complete a three-dose regimen. Another 50 women, considered to be at low risk for postoperative febrile morbidity, were not given antibiotic prophylaxis. Outcomes of febrile morbidity (18% vs 12%) and particularly morbidity caused by endometritis (6% vs 8%, respectively) were similar for single-dose and three-dose groups. In the untreated low-risk group there were no cases of endometritis and the febrile morbidity was comparable to that of the prophylactically treated groups (14% vs 15%). Single-dose cefazolin prophylaxis appears to be comparable to multidose prophylaxis in reducing febrile morbidity after cesarean section.  相似文献   
110.
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