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   3631篇
  免费   170篇
  国内免费   26篇
耳鼻咽喉   29篇
儿科学   50篇
妇产科学   95篇
基础医学   425篇
口腔科学   183篇
临床医学   266篇
内科学   798篇
皮肤病学   111篇
神经病学   400篇
特种医学   120篇
外科学   556篇
综合类   32篇
预防医学   285篇
眼科学   43篇
药学   190篇
中国医学   21篇
肿瘤学   223篇
  2023年   24篇
  2022年   55篇
  2021年   109篇
  2020年   52篇
  2019年   75篇
  2018年   97篇
  2017年   75篇
  2016年   60篇
  2015年   88篇
  2014年   147篇
  2013年   148篇
  2012年   256篇
  2011年   280篇
  2010年   165篇
  2009年   132篇
  2008年   253篇
  2007年   231篇
  2006年   205篇
  2005年   185篇
  2004年   181篇
  2003年   159篇
  2002年   169篇
  2001年   59篇
  2000年   60篇
  1999年   53篇
  1998年   25篇
  1997年   41篇
  1996年   24篇
  1995年   16篇
  1994年   13篇
  1993年   10篇
  1992年   35篇
  1991年   23篇
  1990年   27篇
  1989年   34篇
  1988年   17篇
  1987年   17篇
  1986年   20篇
  1985年   18篇
  1984年   20篇
  1983年   19篇
  1982年   11篇
  1980年   12篇
  1979年   16篇
  1976年   10篇
  1974年   8篇
  1973年   10篇
  1972年   8篇
  1971年   8篇
  1969年   8篇
排序方式: 共有3827条查询结果,搜索用时 11 毫秒
91.
92.
The recent increase in the detection of papillary thyroid carcinoma (PTC) has been influenced by the finding of incidental tumours. To this group, carcinomas measuring less than 1 cm (the so-called microcarcinomas) as well as those above 1 cm belong. Analyzing a case series from our own experience, this paper focuses on the current pre-operative diagnostic challenges that can lead to PTC incidental discovery. For this retrospective study, 287 patients with a PTC diagnosis were selected. For each, the following variables were analysed: sex, age, ultrasound (US) appearance, number of thyroid nodules, PTC size, PTC variants and presence of other associated pathology. Pre-operative fine needle aspiration (FNA) results were classified according to the five-tiered SIAPEC system. For 281 patients, the US-guided FNA results were available. Cytohistological correlation was evaluated in terms of FNA sensitivity and false negative rate. An incidental PTC was found in 45.2 % of patients. The majority of these were due to unsuccessful US detection of malignant nodules (103 cases); incorrect cytological diagnosis was responsible for the other 24 cases. The most powerful clinical confounding factors were: multinodular background versus single nodule presentations (p?p?2 cm) due to tumour heterogeneity. Although with limitations related to the tumour’s intrinsic features and the thyroid background, US-guided FNA, especially if performed by a dedicated multidisciplinary team, is a powerful diagnostic tool for detecting malignant thyroid nodules. To the state of the art, we propose a practical clinical-pathological cut-off for this procedure, setting it at 5 mm.  相似文献   
93.
Pseudohypoaldosteronism type II is a salt-sensitive form of hypertension with hyperkalemia in humans caused by mutations in the with-no-lysine kinase 4 (WNK4). Several studies have shown that WNK4 modulates the activity of the renal Na(+)Cl(-) cotransporter, NCC. Because the renal consequences of WNK4 carrying pseudoaldosteronism type II mutations resemble the response to intravascular volume depletion (promotion of salt reabsorption without K(+) secretion), a condition that is associated with high angiotensin II (AngII) levels, it has been proposed that AngII signaling might affect WNK4 modulation of the NCC. In Xenopus laevis oocytes, WNK4 is required for modulation of NCC activity by AngII. To demonstrate that WNK4 is required in the AngII-mediated regulation of NCC in vivo, we used a total WNK4-knockout mouse strain (WNK4(-/-)). WNK4 mRNA and protein expression were absent in WNK4(-/-) mice, which exhibited a mild Gitelman-like syndrome, with normal blood pressure, increased plasma renin activity, and reduced NCC expression and phosphorylation at T-58. Immunohistochemistry revealed normal morphology of the distal convoluted tubule with reduced NCC expression. Low-salt diet or infusion of AngII for 4 d induced phosphorylation of STE20/SPS1-related proline/alanine-rich kinase (SPAK) and of NCC at S-383 and T-58, respectively, in WNK4(+/+) but not WNK4(-/-) mice. Thus, the absence of WNK4 in vivo precludes NCC and SPAK phosphorylation promoted by a low-salt diet or AngII infusion, suggesting that AngII action on the NCC occurs via a WNK4-SPAK-dependent signaling pathway. Additionally, stimulation of aldosterone secretion by AngII, but not by a high-K(+) diet, was impaired in WNK4(-/-) mice.  相似文献   
94.
95.
96.
97.
The use of a 2-stage inlay technique in atrophic posterior mandibles with more than 10-mm thickness and less than 5-mm height above the inferior alveolar nerve is described. The first surgical procedure was a basic corticotomy of the buccal and lingual bone. One month later, a complete inlay procedure was performed. Computed tomography and conventional radiography showed a mean vertical bone gain of 11.5 mm. This 2-stage inlay technique avoids the use of chisels to complete bone osteotomy and reduces postsurgical nerve disturbances in atrophic posterior mandibles. This technique reduces intraprocedure and postoperative patient discomfort.  相似文献   
98.
99.

Introduction

The frequency of aac(6′)-Ib-cr gene in ESBL-producing strains of Klebsiella pneumoniae and Escherichia coli is unknown, in Chile.

Methodology

The aac(6′)-Ib and aac(6’)-Ib-cr genes were investigated using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and sequencing, in strains isolated from 10 Chilean hospitals between 2008-2009.

Results

The aac(6’)-Ib-cr gene was detected in 54% of K. pneumoniae and 74% of E. coli strains. The CIM50 of CIP was higher among strains harboring aac(6’)-Ib-cr, 8 times higher in K. pneumoniae and 4 times higher in E. coli. Moreover, both aac(6’)-Ib and aac(6’)-Ib-cr were simultaneously found in 13 K. pneumoniae and 3 E. coli isolates.

Conclusion

This is the first report of aac(6’)-Ib-cr in ESBL-producing strains of K. pneumoniae and E. coli isolated from in-patients in Chilean hospitals located along an area of more than 2,800 Km.  相似文献   
100.
Major depressive disorder is prevalent worldwide, and only about half of those affected will experience no further episodes or symptoms. Additionally, depressive symptoms can be challenging to identify, with many patients going undiagnosed despite a wide variety of available treatment options. Antidepressants are the cornerstone of depression treatment; however, a large number of factors must be considered in selecting the treatment best suited to the individual. To help support physicians in this process, international and national treatment guidelines have been developed. This review evaluates the current use of antidepressant treatment for major depressive disorder in six Asian countries (China, Korea, Malaysia, Philippines, Taiwan, and Thailand). No remarkable differences were noted between Asian and international treatment guidelines or among those from within Asia as these are adapted from western guidelines, although there were some local variations. Importantly, a shortage of evidence‐based information at a country level is the primary problem in developing guidelines appropriate for Asia, so most of the guidelines are consensus opinions derived from western research data utilized in western guidelines. Treatment guidelines need to evolve from being consensus based to evidence based when evidence is available, taking into consideration cost/effectiveness or cost/benefit with an evidence‐based approach that more accurately reflects clinical experience as well as the attributes of each antidepressant. In everyday practice, physicians must tailor their treatment to the patient's clinical needs while considering associated external factors; better tools are needed to help them reach the best possible prescribing decisions which are of maximum benefit to patients.  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