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   2133篇
  免费   109篇
  国内免费   18篇
耳鼻咽喉   55篇
儿科学   163篇
妇产科学   63篇
基础医学   154篇
口腔科学   62篇
临床医学   234篇
内科学   446篇
皮肤病学   48篇
神经病学   112篇
特种医学   261篇
外科学   368篇
综合类   37篇
预防医学   61篇
眼科学   28篇
药学   105篇
中国医学   14篇
肿瘤学   49篇
  2024年   3篇
  2023年   19篇
  2022年   15篇
  2021年   40篇
  2020年   20篇
  2019年   28篇
  2018年   46篇
  2017年   27篇
  2016年   47篇
  2015年   64篇
  2014年   71篇
  2013年   86篇
  2012年   103篇
  2011年   98篇
  2010年   90篇
  2009年   107篇
  2008年   111篇
  2007年   95篇
  2006年   121篇
  2005年   93篇
  2004年   93篇
  2003年   80篇
  2002年   90篇
  2001年   30篇
  2000年   19篇
  1999年   19篇
  1998年   52篇
  1997年   58篇
  1996年   74篇
  1995年   58篇
  1994年   50篇
  1993年   47篇
  1992年   14篇
  1991年   7篇
  1990年   14篇
  1989年   35篇
  1988年   31篇
  1987年   32篇
  1986年   33篇
  1985年   25篇
  1984年   15篇
  1983年   9篇
  1982年   22篇
  1981年   14篇
  1980年   8篇
  1979年   2篇
  1978年   5篇
  1977年   13篇
  1976年   12篇
  1975年   13篇
排序方式: 共有2260条查询结果,搜索用时 19 毫秒
51.
Hellenic Journal of Surgery - Hepatolithiasis is the presence of stones within the intrahepatic bile ducts, regardless of common bile duct and gallbladder stones. It is rarely seen in our country...  相似文献   
52.

Background and Objectives:

In this retrospective study, nature, clinical presentations, diagnostic modalities, and endoscopic treatment of urinary system foreign bodies were evaluated.

Methods:

A total of 8 cases were treated with endoscopic surgery between February 15, 2007 and June 12, 2012. Clinical findings, radiologic diagnosis, and management were reviewed.

Results:

We observed that urinary tract foreign bodies were generally secondary to iatrogenic causes; however, bladder/urethral foreign bodies could also be due to self-insertion. Clinical findings were different secondary to their location in the urinary system. All foreign bodies were treated endoscopically.

Conclusions:

Foreign bodies of the urinary system can successfully be treated with endoscopic modalities without any complications.  相似文献   
53.
To understand the hematopoietic and nonhematopoietic responses to interleukin-3 (IL-3), expression of cell-surface IL-3 receptors (IL-3R) was examined on bone marrow (BM) cells and peripheral blood (PB) cells of rhesus monkeys during the course of in vivo IL-3 treatment. Whereas IL-3R expression is low in untreated monkeys, IL-3 administration led to a gradual increase in both low- and high-affinity binding sites for IL-3. This increase reflected the total number of cells expressing IL- 3Rs, as detected by flow cytometry using biotinylated IL-3. Most of these IL-3R+ cells in both BM and PB could be characterized as basophilic granulocytes that contained high levels of histamine. In contrast to the effect on these differentiated cells, IL-3 administration did not significantly alter the low level IL-3R expression on immature, CD34+ cells. Further flow cytometric analysis using biotinylated growth factors showed that the IL-3R+ basophils also expressed receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), but not for IL-6 or Kit ligand. These findings indicated that the IL-3R+ cells included neither monocytes, which express GM-CSFRs and IL-6Rs abundantly, nor mast cells, which express c- kit. By combining flow cytometric and Scatchard data, it was calculated that the basophils contain as many as 1 to 2 x 10(3) high-affinity IL- 3Rs and 15 to 30 x 10(3) low-affinity sites. The finding that in vivo IL-3 treatment leads to the production of large numbers of cells that express high levels of IL-3R and are capable of producing histamine provides an explanation for the often severe allergic reactions that occur during prolonged IL-3 administration. It also indicates that IL- 3, in addition to its direct effects on hematopoietic cells, may also stimulate hematopoiesis through the release of secondary mediators such as histamine by IL-3-responsive mature cells.  相似文献   
54.
55.
We sought to investigate whether application of topical tetracycline has a limiting effect on seroma formation in patients undergoing hernia repair using a polypropylene mesh. This study was conducted in 96 patients undergoing an elective groin hernia repair. Patients were randomized and divided into 2 groups. After the graft was placed, and before external oblique muscle aponeurosis was closed, 5 mL tetracycline was administered on the graft in the tetracycline group (tetra group, n = 50), and 5 mL isotonic saline was administered in the control group (n = 46) without putting in a drain. Seroma checks via surface ultrasonography were done. Seroma amounts measured on the first day were significantly higher in the tetra group (P = 0.04). There were no significant differences regarding seroma measurements on the seventh day or in the first and second months. Topical tetracycline application has no limiting effect on seroma formation after a groin hernia operation.Key words: Lichtenstein technique, Polypropylene mesh, Topical tetracycline, Seroma, UltrasonographyHernia operations are among the most frequently performed surgical operations. Graft use to repair the defect is commonplace because graft use decreases recurrence rate, and defect closure in large abdominal hernias is easier with a mesh.1 The most commonly used and least expensive mesh is the polypropylene mesh. This mesh causes a foreign-body reaction where it is placed, which leads to seroma formation.2 Repeat aspirations of seromas cause infection, and recurrence is seen on follow-up, especially in large hernias.2 While drain use is not recommended in groin hernias, drain use in other abdominal-wall hernias is left to the physician''s discretion. The biggest problem with drain use is transport of the infection by an ascending route.3Tetracycline is an antibiotic, the solution form of which is topically used for pleurodesis in chest surgery.4 Some researchers also report successful topical use of its solution in seroma treatment, taking advantage of its sclerosing effect in cases with breast carcinoma.5,6 Tetracycline has demonstrated increased growth factor–like activity in mesothelial cells exposed to tetracycline leading to fibroblast proliferation.7 This study sought to investigate whether tetracycline has a reducing effect on seroma development in cases undergoing elective groin hernia repair using a polypropylene mesh.  相似文献   
56.

Objective

The synaptosomal-associated protein of 25 kDa (SNAP-25) gene is a presynaptic plasma membrane protein and an integral component of the vesicle docking and fusion machinery mediating secretion of neurotransmitters. Previously, several studies reported association between SNAP-25 and attention deficit hyperactivity disorder (ADHD). We investigated whether these SNAP-25 polymorphisms (MnlI T/G and DdelI T/C) were also associated with ADHD in the Turkish population.

Methods

Our study comprised unrelated 139 subjects who met DSM-IV criteria for ADHD and 73 controls and all were of Turkish origin. Genetic analyses were performed and patients were evaluated with Wender-Utah Rating Scale and Adult ADD/ADHD DSM IV-Based Diagnostic Screening and Rating Scale.

Results

SNAP-25 DdelI polymorphism was not associated with ADHD but there was a statistically significant difference between ADHD patients and controls for SNAP-25 MnlI polymorphism. For SNAP-25 MnlI polymorphism patients with G/G genotype of the SNAP-25 gene MnlI polymorphism had higher Wender-Utah scores and higher scores in the 1st and 3rd parts of adult ADD/ADHD Scale.

Conclusion

We detected a significant association of the MnlI polymorphism in our ADHD sample which was similar to previous findings. Our study also revealed that SNAP-25 MnlI polymorphism was also associated with symptom severity of ADHD. This study is also, the first report on the association of SNAP-25 with ADHD in the Turkish population.  相似文献   
57.
The aim of this study was to determine the Mediterranean fever (MEFV) gene mutations and their clinical correlations in children with familial Mediterranean fever (FMF) in southeast Turkey. Clinical and laboratory characteristics of 147 (65 males, 82 females) consecutive children with FMF having a positive MEFV gene mutation were prospectively investigated. Patients with negative MEFV gene mutations or atypical FMF presentations and those from other regions of the country were excluded. Clinical manifestations and disease severity scores were recorded. The six most frequent MEFV mutations including M694V, V726A, R726H, P369S, E148Q and P369S were investigated by a reverse hybridization test method. The median age of study group was 9.0 years, median age at diagnosis was 7.8 years, median age at disease onset was 5.0 years, and median follow-up duration was 4.0 years. A positive family history of FMF and parent-to-offspring transmission was found in 58.5 and 42.2 % of families, respectively. The frequencies of independent alleles, with decreasing order, were E148Q (30.7 %), M694V (26.0 %), R761H (13.5 %), V726A (13.0 %), P369S (10.5 %) and M680I (6.3 %) in FMF patients. The M694V subgroup had higher mean disease severity score and longer attack duration compared with E148Q and other mutations subgroups (p < 0.05). Two patients with amyloidosis had the M694V homozygote genotype. In conclusion contrast to other regions and many other ethnicities of the world, the most frequent MEFV gene mutation was E148Q in southeast Turkey. The M694V mutation frequency was lower, and disease severity was relatively mild in FMF children of this region.  相似文献   
58.

Background

We aimed to investigate the correlation between ECG QRS voltage changes, N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and clinical improvement in decompensated heart failure (DHF).

Methods and results

DHF patients (n = 56) with a mean age of 67.5 ± 12.6 years showed limb QRS amplitude increase and NT-proBNP level decrease with clinical improvement (p < 0.001). Significant correlation was found between percent changes (Δ%) in body weight and Δ% in QRS voltages of aVR, aVF, DII, ΣQRSI + II and ΣQRS (all limb-leads) (r = − 0.40; r = − 0.35; r = − 0.32; r = − 0.30; r = − 0.30 respectively, p < 0.05). No correlation was found between Δ% in NT-proBNP and body weight (r = − 0.23, p = 0.09). Δ% NT-proBNP was correlated with Δ% QRS voltage only in aVR (r = − 0.312, p = 0.019). In ROC analysis, ≥ 0.5 mm increase in aVR QRS voltage was found to predict ≥ 5 kg weight loss with a sensitivity of 74% and specificity of 62% (p = 0.013, AUC: 0.699).

Conclusions

Increase in QRS voltages especially in aVR was found to be more sensitive than NT-proBNP to predict clinical improvement in DHF.  相似文献   
59.
60.
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