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   299307篇
  免费   15765篇
  国内免费   410篇
耳鼻咽喉   4233篇
儿科学   10323篇
妇产科学   10320篇
基础医学   45125篇
口腔科学   7523篇
临床医学   24389篇
内科学   56187篇
皮肤病学   6320篇
神经病学   21179篇
特种医学   11660篇
外国民族医学   43篇
外科学   46829篇
综合类   7772篇
现状与发展   1篇
一般理论   162篇
预防医学   20022篇
眼科学   6956篇
药学   20968篇
  4篇
中国医学   790篇
肿瘤学   14676篇
  2019年   2328篇
  2018年   3645篇
  2017年   2682篇
  2016年   3093篇
  2015年   3510篇
  2014年   4602篇
  2013年   7259篇
  2012年   9116篇
  2011年   9499篇
  2010年   6156篇
  2009年   5576篇
  2008年   8715篇
  2007年   9563篇
  2006年   9405篇
  2005年   8989篇
  2004年   8717篇
  2003年   8208篇
  2002年   7784篇
  2001年   13357篇
  2000年   13678篇
  1999年   11454篇
  1998年   3044篇
  1997年   2796篇
  1996年   2648篇
  1995年   2562篇
  1994年   2358篇
  1992年   8334篇
  1991年   8470篇
  1990年   8284篇
  1989年   8094篇
  1988年   7340篇
  1987年   7095篇
  1986年   6739篇
  1985年   6543篇
  1984年   4780篇
  1983年   4138篇
  1982年   2483篇
  1979年   4442篇
  1978年   3234篇
  1977年   2732篇
  1976年   2510篇
  1975年   2841篇
  1974年   3361篇
  1973年   3368篇
  1972年   3123篇
  1971年   2952篇
  1970年   2840篇
  1969年   2590篇
  1968年   2546篇
  1967年   2380篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
alpha 1-Antiproteinase is the major inhibitor of proteolytic enzymes, such as elastase, in human plasma. Its elastase-inhibitory capacity can be inactivated by exposure to hydroxyl radicals (.OH) generated either by pulse radiolysis or by an Fe3+-EDTA/H2O2/ascorbic acid system. Inactivation of alpha 1-antiproteinase by radiolytically-generated .OH under anoxic conditions was decreased by adding a range of anti-inflammatory drugs to the reaction mixtures, including the thiol compound penicillamine. However, under conditions favouring formation of oxysulphur radicals, protection by thiols such as penicillamine was much decreased. It is proposed that sulphur-containing radicals resulting from attack of biologically-produced oxidants upon penicillamine in the presence of O2 can themselves inactivate alpha 1-antiproteinase, and that such radicals might contribute to the side-effects produced by penicillamine or gold thiol therapy in rheumatoid arthritis.  相似文献   
102.
A lawsuit directed by parents at a day care program following an outbreak of infectious disease would most likely be based on the legal theory of negligence--the failure to exercise due care as required by circumstances. In the determination of liability for infectious diseases in child day care, the element of causation is most critical. Did the day care facility's actions or failure to act cause the harm? Another important question is whether an infectious disease can be occupational and under what circumstances. Although worker's compensation laws initially had no provisions for occupational disease, now all states recognize responsibility for them. Awareness of potential problems with legal liability and establishment of procedures to minimize risk are important for day care providers, public health officials, clinicians, and parents.  相似文献   
103.
Synovectomy of the knee in patients with hemophilia presenting in countries with demographic characteristics that make central referral difficult is the subject of this article. Ten patients, six surgeons, and two countries contributed to this study, which demonstrated that approximately 40% of these patients had no further hemarthroses into the affected joint and the remainder had reduced frequency and severity of bleeding. Continuous passive motion has an important place in postoperative management, and manipulation with the patient under anesthesia is of doubtful value. The possible relationship between diminished range of movement and a successful outcome in terms of abolition of hemorrhage is explored. One patient underwent synovectomy of the knee without complication; the other nine suffered significant complications.  相似文献   
104.
Four psychiatric syndromes related to reproductive function in women have been identified: postpartum depression, premenstrual syndrome (PMS), post-hysterectomy depression, and involutional melancholia. The authors review what is known about these syndromes and conclude, first, that postpartum depression comprises three separate syndromes, the most severe of which is most likely a variant of primary affective disorder. Second, research into the syndromal nature, biology, and treatment of PMS is still in its infancy due to a variety of methodological difficulties. Third, the rate of depression among women during the involutional period or following hysterectomy for benign pathology is not higher than it is at other times.  相似文献   
105.
106.
Enoximone is a positive inotropic agent belonging to the group of phosphodiesterase F-III inhibitors. The drug was tested in 34 patients uncontrolled by sympathomimetic drugs and referred to our department for urgent heart transplantation or circulatory assistance. After insertion of a Swan-Ganzgatheter and a radial artery catheter for haemodynamic monitoring, enoximone was administered as a 15-minute intravenous bolus injection of 1 to 2.5 mg/kf every 8 hours, in addition to sympathomimetic agents. Clinical and haemodynamic improvement was observed after thirty minutes in 30 patients. The cardiac index rose from 1.82 to 2.67 l/min/m2 and the pulmonary wedge pressure fell from 30.8 to 18.9 mmHg. Systemic arterial resistance decreased from 2170 to 1520 dyn. s. cm-5, and pulmonary resistance from 5.5 to 4.6 Wood units (p less than 0.01 for all values). Four patients had no haemodynamic improvement and were put on circulatory assistance, using a Jarvik 7 total artificial heart in 3 of them and heterotopic circulatory assistance in one. After clinical investigation for contra-indication to heart transplantation, and as their improved haemodynamic status permitted, 12 of the 30 patients were considered suitable (group B) for heart transplantation. Transplantation was performed within a week of admission in 11 patients without any need for mechanical assistance. One of the group B patients who required implantation of a Jarvik 7 artificial heart died after 12 hours of assistance. Eighteen patients were considered unsuitable for transplantation (group A) and treated medically.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
107.
108.
Diesters based on isosteviol and dicarboxylic acids were synthesized and tested for antituberculous activity. Isosteviol and some of its derivatives exhibit appreciable tuberculostatic properties in vitro, the activity being dependent on the length of the polymethylene spacer connecting two ent-beyeran fragments. The mechanism of the antituberculous action of isosteviol derivatives are discussed. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 9, pp. 12–13, September, 2006.  相似文献   
109.
110.
BACKGROUND: The present study investigated the use of acupuncture analgesia in maxillofacial surgery. PATIENTS AND METHODS: Acupuncture analgesia was applied in 120 patients. In 20 of these, surgery was carried out under general anaesthesia in combination with acupuncture analgesia. In 100 patients, acupuncture analgesia was applied in addition to traditional postoperative analgesia. In case of troublesome postoperative pain, it was necessary to carry out additional sessions (1-4) of acupuncture stimulation. RESULTS: When acupuncture analgesia was used, the pulse rate and blood pressure during surgery generally remained stable. In the present study serum cortisol was also measured and showed only minor elevation. DISCUSSION: The present study demonstrated favourable results when the first variant of the brake method of acupoint stimulation was used for 40-50 min with additional manual twirling of the needles. This involved inserting needles into the acupoints and, using slow, rolling manual movements increasing the amplitude step-by-step provoking simultaneous especially strong patient sensations. CONCLUSION: Acupuncture analgesia can be a useful adjunct to conventional anaesthesia in maxillofacial surgery.  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