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   5764篇
  免费   413篇
  国内免费   18篇
耳鼻咽喉   86篇
儿科学   92篇
妇产科学   76篇
基础医学   1030篇
口腔科学   74篇
临床医学   589篇
内科学   1223篇
皮肤病学   153篇
神经病学   522篇
特种医学   322篇
外科学   647篇
综合类   31篇
一般理论   2篇
预防医学   341篇
眼科学   114篇
药学   417篇
中国医学   10篇
肿瘤学   466篇
  2023年   26篇
  2022年   82篇
  2021年   150篇
  2020年   67篇
  2019年   118篇
  2018年   139篇
  2017年   123篇
  2016年   149篇
  2015年   192篇
  2014年   208篇
  2013年   266篇
  2012年   381篇
  2011年   453篇
  2010年   248篇
  2009年   291篇
  2008年   428篇
  2007年   391篇
  2006年   425篇
  2005年   393篇
  2004年   411篇
  2003年   354篇
  2002年   302篇
  2001年   64篇
  2000年   48篇
  1999年   43篇
  1998年   66篇
  1997年   62篇
  1996年   32篇
  1995年   31篇
  1994年   27篇
  1993年   18篇
  1992年   16篇
  1991年   13篇
  1990年   11篇
  1989年   10篇
  1988年   8篇
  1986年   11篇
  1985年   7篇
  1984年   6篇
  1982年   14篇
  1981年   7篇
  1980年   6篇
  1979年   7篇
  1978年   10篇
  1977年   4篇
  1975年   4篇
  1974年   8篇
  1973年   7篇
  1971年   4篇
  1970年   4篇
排序方式: 共有6195条查询结果,搜索用时 10 毫秒
81.
82.
83.
Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (ι-toxin and binary enterotoxin, or BEC), Clostridium spiroforme (C. spiroforme toxin or CST), as well as Bacillus cereus (vegetative insecticidal protein or VIP). These gut-acting proteins form an AB complex composed of ADP-ribosyl transferase (A) and cell-binding (B) components that intoxicate cells via receptor-mediated endocytosis and endosomal trafficking. Once inside the cytosol, the A components inhibit normal cell functions by mono-ADP-ribosylation of globular actin, which induces cytoskeletal disarray and death. Important aspects of each bacterium and binary enterotoxin will be highlighted in this review, with particular focus upon the disease process involving the biochemistry and modes of action for each toxin.  相似文献   
84.
Medical literature abounds with reports on injuries and fatalities caused by airgun projectiles. While round balls or diabolo pellets have been the standard projectiles for airguns for decades, today, there are a large number of different airgun projectiles available. A very uncommon — and until now unique — discarding sabot airgun projectile (Sussex Sabo Bullet) was introduced into the market in the 1980s. The projectile, available in 0.177 (4.5 mm) and 0.22 (5.5 mm) caliber, consists of a plastic sabot cup surrounding a subcaliber copper-coated lead projectile in typical bullet shape. Following the typical principle of a discarding sabot projectile, the lightweight sabot is supposed to quickly loose velocity and to fall to the ground downrange while the bullet continues on target. These sabot-loaded projectiles are of special forensic interest due to their non-traceability and ballistic parameters. Therefore, it is the aim of this work to investigate the ballistic performance of these sabot airgun projectiles by high-speed video analyses and by measurement of the kinetic parameters of the projectile parts by a transient recording system as well as observing their physical features after being fired. While the sabot principle worked properly in high-energy airguns (E?>?17 J), separation of the core projectile from the sabot cup was also observed when discharged in low-energy airguns (E?<?7.5 J). While the velocity of the discarded Sussex Sabo core projectile was very close to the velocity of a diabolo-type reference projectile (RWS Meisterkugel), energy density was up to 60 % higher. To conclude, this work is the first study to demonstrate the regular function of this uncommon type of airgun projectile.  相似文献   
85.
86.
87.
Adjustable loop button fixations are commonly applied in anterior cruciate ligament (ACL) surgery. In the following case of a young female soccer player, the combination of soft tissue interposition and tunnel malplacement led to an accidental tenodesis of the quadriceps tendon. This resulted in a massive restriction of the joint function which was resolved by arthroscopic removal of the transplant and fixation. The patient gained full range of motion 8 weeks postoperatively.  相似文献   
88.
89.
Background The rate of preterm births in Germany is 8.6%, which is very high compared to other European countries. As preterm birth contributes significantly to perinatal morbidity and mortality rates, the existing prevention strategies need to be optimized and expanded further. About ⅔ of all women with preterm birth have preterm labor or premature rupture of membranes. They are bracketed together under the term “spontaneous preterm birth” as opposed to iatrogenic preterm birth, for example as a consequence of preeclampsia or fetal growth retardation. Recent studies suggest that low-dose aspirin does not just reduce the rate of iatrogenic preterm births but can also further reduce the rate of spontaneous preterm births. This review article presents the current state of knowledge. Method A selective literature search up until April 2020 was done in PubMed, using the terms “randomized trial”, “randomized study”, “spontaneous preterm birth”, and “aspirin”. Results Secondary analyses of prospective randomized studies on the prevention of preeclampsia with low-dose aspirin show that this intervention also significantly reduced the rate of spontaneous preterm births in both high-risk and low-risk patient populations. The results of the ASPIRIN trial, a prospective, randomized, double-blinded multicenter study carried out in six developing countries, also point in this direction, with the figures showing that the daily administration of 81 mg aspirin starting before 14 weeks of gestation lowered the preterm birth rate of nulliparous women without prior medical conditions by around 11% (11.6 vs. 13.1%; RR 0.89; 95% CI: 0.81 – 0.98, p = 0.012). Conclusion Further studies on this issue are urgently needed. If these confirm the currently available results, then it would be worth discussing whether general aspirin prophylaxis for all pregnant women starting at the latest in 12 weeks of gestation is indicated. Key words: spontaneous preterm birth, iatrogenic preterm birth, prevention, preeclampsia, aspirin  相似文献   
90.
Follow-up after curative treatment of patients with gastrointestinal cancers aims to detect recurrent disease and to provide curative treatment to prolong overall survival if possible. This, however, has only been shown for colorectal cancers. Regular visits including testing of carcinoembryonic antigen and appropriate staging has been shown to enable curative treatment even in relapse. For other gastrointestinal cancers, positive effects of regular follow-up visits on survival have not been shown so far. This is mostly also due to lacking curative treatment strategies in case of relapse. In these cases, follow-up is recommended for providing palliative treatment, detecting recurrence for quality issues, treating complications or symptoms due to relapse, and providing psychological support. This review will give a brief overview about the current follow-up issues in colorectal, esophagogastric, and pancreatic cancers, as these are clinically the most relevant.  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