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   303421篇
  免费   19787篇
  国内免费   6613篇
耳鼻咽喉   2860篇
儿科学   9655篇
妇产科学   4253篇
基础医学   37488篇
口腔科学   7391篇
临床医学   26858篇
内科学   48458篇
皮肤病学   5213篇
神经病学   16502篇
特种医学   9464篇
外国民族医学   27篇
外科学   40116篇
综合类   33433篇
现状与发展   14篇
一般理论   25篇
预防医学   20236篇
眼科学   6726篇
药学   28191篇
  20篇
中国医学   11424篇
肿瘤学   21467篇
  2023年   5475篇
  2022年   8959篇
  2021年   11887篇
  2020年   9439篇
  2019年   17011篇
  2018年   14361篇
  2017年   9699篇
  2016年   7094篇
  2015年   8090篇
  2014年   13272篇
  2013年   12678篇
  2012年   10426篇
  2011年   15002篇
  2010年   11090篇
  2009年   11851篇
  2008年   11142篇
  2007年   12708篇
  2006年   11584篇
  2005年   11445篇
  2004年   9546篇
  2003年   8294篇
  2002年   7091篇
  2001年   7206篇
  2000年   7313篇
  1999年   7233篇
  1998年   5992篇
  1997年   4664篇
  1996年   3987篇
  1995年   3450篇
  1994年   3157篇
  1993年   2595篇
  1992年   2398篇
  1991年   2053篇
  1990年   1821篇
  1989年   1554篇
  1988年   1517篇
  1987年   1165篇
  1985年   3526篇
  1984年   4809篇
  1983年   3374篇
  1982年   3417篇
  1981年   3135篇
  1980年   2786篇
  1979年   2564篇
  1978年   2096篇
  1977年   1802篇
  1976年   1956篇
  1975年   1601篇
  1974年   1430篇
  1973年   1336篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
BackgroundLymph node recurrences (LNR) from colorectal cancer (CRC) still represent a therapeutic challenge, as standardized recommendations have yet to be established. The aim of this study was to analyze short- and long-term oncological outcomes following resection of LNR from CRC.MethodsAll patients with previously resected CRC who underwent histopathologically confirmed LNR resection in 3 tertiary referral centers between 2010 and 2017 were reviewed. Short- and long-term outcomes were analyzed, mainly recurrence-free and overall survival. Further recurrences following LNR resection were also analyzed.ResultsOverall, 18 patients were included. Primary CRC was left-sided in 16 (89%) patients, staged T3-4 in 15 (83%), N+ in 14 (78%) and presented with synchronous metastases in 8 (43%). Median time interval between primary CRC and LNR resections was 31 months. Performed lymphadenectomies were aortocaval (n = 10), pelvic (n = 7), in hepatic pedicle (n = 3) and mesenteric (n = 1). Four patients had associated liver metastases resection. Three (17%) presented with postoperative complications, of which one Clavien-Dindo 3. Fourteen (78%) patients presented with further recurrences after a mean delay of 9 months, with 36% of patients presenting with early (<6 months) recurrence. Five (36%) patients could undergo secondary recurrence resection and 3 (21%) patients radiotherapy. Median overall survival following LNR resection reached 44 months.ConclusionsCurrent results suggest that LNR resection is feasible and associated with improved survival, in selected patients. Longer time interval between primary CRC resection and LNR occurrence appeared to be a favorable prognostic factor whereas multisite recurrence appeared to be associated with impaired long-term survival.  相似文献   
53.
54.
55.
56.
57.
58.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
59.
Potential for widespread transmission of HIV/AIDS among American Indian (AI) adolescents exists, yet no evidence-based interventions (EBIs) have been adapted and evaluated with this population. Intensive psychoeducation may improve knowledge and decision-making which could potentially translate to reductions in HIV risk behaviors. A peer group randomized controlled comparison of an adapted EBI vs. control was delivered over an eight-day summer basketball camp in one reservation-based tribal community to adolescents ages 13–19. Outcome data were gathered immediately post-camp and at 6 and 12 months follow-up. Self-selected peer groups were randomized to intervention (n = 138) or control (n = 129) conditions for a total sample of 267 participants (56.2% female), mean age 15.1 years (SD = 1.7). Intervention participants had better condom use self-efficacy post-camp (Adjusted Mean Difference [AMD] = ?0.75, p < 0.005) and at 6 (AMD = ?0.44, p < 0.005) and 12 months (AMD = ?0.23, p < 0.05) follow-up. Intervention participants also had higher HIV prevention and transmission knowledge (post-camp: AMD = 0.07, p < 0.01; 6 months: AMD = 0.06, p < 0.01) were more likely to believe condoms prevent sexually transmitted infections (post-camp: RR = 1.41, p < 0.005; 6 months: RR = 1.34, p < 0.05), to talk with an adult about HIV/AIDS (post-camp: RR=1.78, p < 0.005; 6 months: RR = 1.14, p < 0.005), had higher partner negotiation efficacy related to substance use during sex (post-camp: AMD = 0.37, p < 0.01), and were more likely to intend to use a condom (post-camp: RR = 1.39, p < 0.01). The adapted intervention had short- and medium-term impacts on AI adolescent risk for HIV/AIDS, but attenuated at 12 months. Intervention delivery through a community-based camp is feasible and acceptable with strong retention. Additional study is needed to evaluate the adapted intervention's impact on sexual risk behaviors and if booster sessions and parent involvement translate to long-term impacts.  相似文献   
60.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  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