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   17019篇
  免费   549篇
  国内免费   32篇
耳鼻咽喉   916篇
儿科学   505篇
妇产科学   1083篇
基础医学   2116篇
口腔科学   103篇
临床医学   924篇
内科学   3582篇
皮肤病学   189篇
神经病学   1826篇
特种医学   289篇
外科学   1294篇
综合类   62篇
一般理论   1篇
预防医学   1234篇
眼科学   545篇
药学   2408篇
中国医学   39篇
肿瘤学   484篇
  2023年   72篇
  2022年   222篇
  2021年   449篇
  2020年   168篇
  2019年   280篇
  2018年   543篇
  2017年   377篇
  2016年   402篇
  2015年   358篇
  2014年   607篇
  2013年   885篇
  2012年   1049篇
  2011年   1302篇
  2010年   663篇
  2009年   296篇
  2008年   808篇
  2007年   1163篇
  2006年   1222篇
  2005年   1189篇
  2004年   1272篇
  2003年   1250篇
  2002年   1038篇
  2001年   457篇
  2000年   492篇
  1999年   302篇
  1998年   102篇
  1997年   25篇
  1996年   14篇
  1995年   20篇
  1994年   14篇
  1992年   14篇
  1991年   15篇
  1990年   32篇
  1988年   14篇
  1987年   21篇
  1986年   19篇
  1985年   24篇
  1984年   20篇
  1983年   20篇
  1982年   23篇
  1981年   34篇
  1980年   22篇
  1979年   28篇
  1978年   34篇
  1977年   30篇
  1976年   17篇
  1975年   23篇
  1974年   15篇
  1973年   13篇
  1972年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The current literature suggests that the antibacterial effect of leukocyte- and platelet-rich plasma (L-PRP) is directly related to platelet and leukocyte concentrations. The aim of this study was twofold: first, to evaluate the antimicrobial effect of L-PRP against selected bacterial strains in vitro, and second, to correlate this effect with leukocyte and platelet content in the final concentration. Blood was collected from 20 healthy males, and L-PRP, acellular plasma (AP), and autologous thrombin were consecutively prepared. Flow cytometry analysis of the blood, L-PRP, and AP was performed. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against seven selected bacterial strains using the Kirby–Bauer disk-diffusion method. There was notable antimicrobial activity against selected bacterial strains. No statistically significant correlations between antimicrobial activities and the platelet concentration in L-PRP were observed. Statistically significant positive correlations between selected leukocyte subtypes and antimicrobial activity were noted. A negative correlation was found between elevated monocyte count and antimicrobial activity of L-PRP against one bacterial strain studied. L-PRP possesses antimicrobial activity and can be potentially useful in the fight against certain postoperative infections. The bactericidal effect of L-PRP is caused by leukocytes, and there exists a relationship among selected leukocyte subtypes and L-PRP antimicrobial activity.  相似文献   
2.
3.
4.
Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times.  相似文献   
5.
6.
7.
8.
Nine wrists in eight patients were treated surgically between 1988 and 2003 for symptomatic Madelung's deformity. The pain of involved wrist followed by forearm deformation fulfilled criteria for surgery. Closing wedge osteotomy of the distal radius were carried out eight times accompanied by shortening of the ulna (four patients), excision of the distal ulna (one patient), and no ulnar surgery (three patients). Pain relieved after surgery. The follow up period ranged from 1 to 9.5 years. No pour results were stated in subjective patient's estimation during final check up. Wrist appearance were stated to be satisfactory. Limitation of the range of motion concerning supination and pronation of the forearm were stated invariably. X-ray retrospective assessment of the inclination angle, lunate coverage and presence of arthritic changes were conducted. Time and method of surgical treatment for Madelung's deformity should be considered individually.  相似文献   
9.
BACKGROUND: Incisional hernia is a common problem following Roux-en-Y gastric bypass for morbid obesity. PATIENTS AND MATERIALS: We report the preliminary results of nonrandomized prophylactic use of polypropylene mesh in a group of 60 consecutive patients. The patients with highest body mass index, and/or history of abdominal hernias and profound liver damage had abdominal wall reinforced with mesh during an operation. A year later the wound was assessed in all patients. RESULTS: In standard wound closure group (n=48) incisional hernia was found in 9 cases (20%). None of the patients with inserted mesh (n=12) developed hernia. The length of hospital stay in mesh group was similar to that in the nonmesh group and shorter than in patients with hernia occurrence. Mesh insertion was complicated with wound discharge in three patients. CONCLUSIONS: In our opinion prophylactic use of polypropylene mesh in bariatric patients is highly effective in postoperative hernia prevention.  相似文献   
10.
In the presented paper the authors evaluate the long-term results of treatment for inflammatory and thromboembolic complications in knee joint alloplasty with cemented endoprostheses. The clinical material spanning the years 1998-2003 are 15 patients with analysed complications, it determine 9% of all operated. They have evaluated achieved results using the HSS knee rating scale in their own modification. As far as the authors are concerned, venographic examination is a prerequisite for appropriate care of the patients following knee joint alloplasty who might have deep venous thrombosis. It is necessary to provide similar treatment when developing infections are suspected in the perioperative period and in cases of late infections. Consequently, antibiotic therapy and a possible quick bacteriological checkup for healing a postoperative wound is a prerequisite for successful treatment. Achieved results induce statement, that thromboembolic and inflammatory complications caused at most operated chronic vein insufficiency, deficit of range of motion at operated joint and gait insufficiency. Thromboembolic complications was always related with inflammation of knee joint alloplasty in our own material.  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