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   24621篇
  免费   1251篇
  国内免费   78篇
耳鼻咽喉   332篇
儿科学   1380篇
妇产科学   604篇
基础医学   2725篇
口腔科学   557篇
临床医学   1409篇
内科学   5210篇
皮肤病学   768篇
神经病学   1508篇
特种医学   780篇
外科学   3179篇
综合类   757篇
一般理论   15篇
预防医学   1228篇
眼科学   1390篇
药学   2240篇
中国医学   179篇
肿瘤学   1689篇
  2023年   171篇
  2022年   423篇
  2021年   863篇
  2020年   424篇
  2019年   550篇
  2018年   705篇
  2017年   487篇
  2016年   608篇
  2015年   568篇
  2014年   910篇
  2013年   1111篇
  2012年   1568篇
  2011年   1711篇
  2010年   910篇
  2009年   756篇
  2008年   1171篇
  2007年   1219篇
  2006年   1223篇
  2005年   1046篇
  2004年   960篇
  2003年   819篇
  2002年   749篇
  2001年   700篇
  2000年   701篇
  1999年   557篇
  1998年   227篇
  1997年   164篇
  1996年   142篇
  1995年   149篇
  1994年   114篇
  1993年   99篇
  1992年   367篇
  1991年   370篇
  1990年   338篇
  1989年   328篇
  1988年   284篇
  1987年   251篇
  1986年   234篇
  1985年   232篇
  1984年   171篇
  1983年   135篇
  1981年   91篇
  1979年   157篇
  1978年   97篇
  1977年   81篇
  1975年   83篇
  1974年   100篇
  1973年   92篇
  1972年   118篇
  1970年   78篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
A series of bisindolylmethanes (BIMs) (1a7j) including hybrid BIMs 6a6c were prepared for bioevaluation. The results of initial antimicrobial screening of compounds 1a6c showed compounds 2b, 2m, 4a and 5b to be the most potent inhibitors, exhibiting MIC as well as MBC values equal to or less than that of ciprofloxacin (0.5–2 μg/mL) against Staphylococcus aureus, MRSA and VRE. Compound 2m was selected further to study the effect of N,N′ disubstitution towards antibacterial and antitumor activity. It was observed that substitution at N,N′ position (7a7j) of 2m diminishes its antibacterial activity though in vitro antitumour activity against a panel of prostate, cervical and lung cancer cell lines remains more or less intact.  相似文献   
943.
944.

Background

Treatment of esophageal adenocarcinoma often involves surgical resection. Newer technologies in interventional endoscopy have led to a substantial paradigm shift in the management of early-stage neoplasia in Barrett’s esophagus comprising high-grade dysplasia (HGD), intramucosal carcinoma, and, in some cases, submucosal carcinoma. However, there has been no consensus regarding the indications for esophageal preservation in these cases. In this work, consensus guidelines were established for the management of early-stage esophageal neoplasia considering clinically relevant aspects (age, comorbidities, and social environment) in each scenario.

Methods

Seventeen experts were invited to participate based on their background and clinical expertise at high-volume centers. A questionnaire was created that included four clinical scenarios covering a wide range of situations within HGD and/or early esophageal neoplasia, particularly where controversies are likely to exist. Each of the clinical scenarios was open to discussion subdivided by patient age (20, 50, and 80 s). For each clinical scenario an expert was chosen to defend that position. Each defense triggered a subsequent discussion during a consensus meeting. Conclusions of that discussion together with an accompanying literature analysis allowed experts to confirm or change their original choices and served as the basis for the recommendations stated in this article.

Results

There was 100 % consensus supporting esophageal preservation in patients with HGD, independent of patient age or Barrett’s length. In patients with T1a adenocarcinoma, consensus for preservation was not reached (65 %) for young and middle-aged individuals but was supported for elderly patients (100 %). For T1b adenocarcinoma, consensus was reached for surgical resection (90 %), leaving organ preservation for patients with very low risk of nodal invasion or poor surgical candidates.

Conclusion

Advances in endoscopic imaging and therapy allow for organ preservation in most settings of early-stage neoplasia of the esophagus, provided that the patient understands the implications of this decision.  相似文献   
945.
946.

Background

Currently, the long-term advantages of having a pancreas transplantation (PT) are debated, particularly in patients receiving pancreas after kidney (PAK) allografts. The United Network for Organ Sharing (UNOS) requires that a transplant center perform a minimum number of PT per year to remain an active PT center. The long-term outcomes and challenges of PAK in small pancreas transplant centers are not well studied.

Methods

In this retrospective analysis, we report short- and long-term outcomes in a small center performing 2–9 PT annually.

Results

Forty-eight PT (25 simultaneous pancreas and kidney transplantation [SPK], 23 PAK) were performed in our center. Donor and recipient demographics were similar in both groups. All suitable local donors were used for SPK. All organs for PAK transplantation were imported from other UNOS regions. Mean follow-up was 61 ± 46 and 74 ± 46 months for SPK and PAK, respectively. Patient and graft survival rates were similar in SPK and PAK groups and better than the reported national average. Four patients (11%) died (1 due to trauma, 1 brain lymphoma, 1 ruptured aneurysm; and 1 unknown cause). Two patients (4%; 1 SPK, 1 PAK) lost their grafts because of thrombosis on postoperative days 3 and 5 in 2002. No graft thrombosis occurred since 2002. Seven patients (15%) required reoperation (4 for bleeding, 2 anastomotic leaks, 1 small bowel perforation). Two patients (4%) developed post-transplantation lymphoproliferative disease. Five patients (11%) experienced cytomegalovirus antigenemia which responded well to antiviral therapy.

Conclusions

Compared with outcomes for diabetic patients on dialysis, current SPK and PAK short- and long-term results are favorable even in a small PT center. Therefore, unless there is a contraindication, PT should be offered to all type 1 diabetic patients with end-stage renal disease at the time of kidney transplantation or afterward.  相似文献   
947.

Introduction

The optimal treatment of high energy tibial fractures remains controversial and a challenging orthopaedic problem. The role of external fixators for all these tibial fractures has been shown to be crucial.

Methods

A five-year consecutive series was reviewed retrospectively, identifying two treatment groups: Ilizarov and Taylor Spatial Frame (TSF; Smith & Nephew, Memphis, TN, US). Fracture healing time was the primary outcome measure.

Results

A total of 112 patients (85 Ilizarov, 37 TSF) were identified for the review with a mean age of 45 years. This was higher in women (57 years) than in men (41 years). There was no significant difference between frame types (p=0.83). The median healing time was 163 days in both groups. There was no significant difference in healing time between smokers and non-smokers (180 vs 165 days respectively, p=0.07), open or closed fractures (p=0.13) or age and healing time (Spearman''s r=0.12, p=0.18). There was no incidence of non-union or re-fracture following frame removal in either group.

Conclusions

Despite the assumption of the rigid construct of the TSF, the median time to union was similar to that of the Ilizarov frame and the TSF therefore can play a significant role in complex tibial fractures.  相似文献   
948.
The Sturge Weber syndrome is characterized by developmental delay, seizures in infancy, unilateral cutaneous lesions with ipsilateral leptomeningeal enhancement. We report an unusual presentation of Sturge Weber syndrome with bilateral port wine nevus on the trunk and face along with bilateral cortical involvement in a developmentally normal child with progressive megalencephaly.  相似文献   
949.
Symptomatic neurosyphilis (NS) can have varied syndromic presentations: Meningitis, meningovascular and parenchymatous involvement. Non-tabetic syphilis affecting the spinal cord is rare and only sporadic case reports have been published. The variant of meningomyelitis known as Erb''s paraplegia refers to patients of spinal syphilis with very slow progression over many years and predominantly motor signs. Primary optic atrophy occurs twice as frequently in tabes dorsalis as in other types of NS. We describe here a case of a 32-year-old truck driver who presented with Erb''s paraplegia with primary optic atrophy. This clinical overlap in NS is extremely rare and to our knowledge is the first case report of its type.  相似文献   
950.
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