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   995935篇
  免费   76709篇
  国内免费   2613篇
耳鼻咽喉   12961篇
儿科学   34465篇
妇产科学   28460篇
基础医学   145281篇
口腔科学   27713篇
临床医学   90265篇
内科学   193545篇
皮肤病学   22913篇
神经病学   79105篇
特种医学   38385篇
外国民族医学   305篇
外科学   149482篇
综合类   23739篇
一般理论   385篇
预防医学   77818篇
眼科学   22606篇
药学   71868篇
  3篇
中国医学   2029篇
肿瘤学   53929篇
  2018年   10555篇
  2017年   8235篇
  2016年   9373篇
  2015年   10594篇
  2014年   14415篇
  2013年   22001篇
  2012年   28980篇
  2011年   30824篇
  2010年   18487篇
  2009年   17435篇
  2008年   28786篇
  2007年   30460篇
  2006年   30959篇
  2005年   29637篇
  2004年   28925篇
  2003年   27798篇
  2002年   26814篇
  2001年   46924篇
  2000年   48034篇
  1999年   40261篇
  1998年   11177篇
  1997年   10095篇
  1996年   10160篇
  1995年   9775篇
  1994年   9090篇
  1993年   8481篇
  1992年   32248篇
  1991年   31458篇
  1990年   31006篇
  1989年   29874篇
  1988年   27167篇
  1987年   27325篇
  1986年   25434篇
  1985年   24601篇
  1984年   18398篇
  1983年   15515篇
  1982年   9289篇
  1981年   8376篇
  1979年   16859篇
  1978年   12218篇
  1977年   10314篇
  1976年   9754篇
  1975年   10178篇
  1974年   12317篇
  1973年   11843篇
  1972年   10884篇
  1971年   10113篇
  1970年   9375篇
  1969年   8724篇
  1968年   8104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Radiation-induced gastrointestinal fistulae.   总被引:2,自引:0,他引:2  
Seventy patients with radiation enteritis presented to a single surgical unit between 1958 and 1984. Of these 10 (14%) had 14 radiation-induced fistulae. The median latent period between radiotherapy and presentation of the fistula was 20 months. The fistulae were often multiple and/or associated with other radiation-induced lesions, patients presenting with fistulae being significantly more likely to have synchronous lesions compared with those who presented with strictures (P = 0.005). These patients are often unfit for major surgery. Wide resection and anastomosis, or exclusion operations are the surgical procedures of choice.  相似文献   
912.
High-frequency jet-ventilation (HFJV) was applied to 30 patients undergoing vertical partial surgery of the larynx for carcinoma of the vocal cords. This technique gave good surgical conditions as it interfered little with the air-ducts. It was carried out with a catheter of only 3 mm external diameter; control of ventilation during surgery was adequate, the average PaO2 being 27.9 +/- 5.6 kPa (209.3 +/- 4.2 mmHg) and the average PaCO2 5.4 +/- 1.4 kPa (40.5 +/- 10.5 mmHg). It avoided also the need for a tracheotomy. In the past, anaesthetic techniques were local anaesthesia combined with neuroleptanalgesia, endotracheal intubation or preoperative tracheotomy. None of these methods being satisfactory, our practice now includes first a nasotracheal intubation with an armoured tube at the beginning of the surgical procedure, followed by HFJV during the removal of the vocal cord, the tracheal tube being slightly pulled out. The tracheal tube is then put back in place before the thyroid cartilage is closed. The contra-indications are the same as those of HFJV. There are two types of complications: complications of HFJV itself, and postoperative complications due to the absence of tracheotomy. No accidents were observed. The only incidents seen were related to the lack of tracheotomy: subcutaneous oedema of the neck during the postoperative period in eight patients and moderate tracheobronchial congestion in five patients.  相似文献   
913.
Zusammenfassung Die posttraumatische Pneumatocele ist eine seltene intrapulmonale Veränderung nach stumpfem Thoraxtrauma. Anhand eines gut dokumentierten Falles wird diese seltene Form der Lungenkontusion dargestellt und die klinisch bedeutsame Differentialdiagnose diskutiert.
Traumatic pneumatocele — a case report
Summary The posttraumatic pneumatocele is a rare intrapulmonary lesion following blunt thoracic injury. By means of a well documented case report this rare form of lung contusion is demonstrated and the clinically important differential diagnosis is discussed.
  相似文献   
914.
The return of fertility following discontinuation of norethisterone oenanthate (NET EN) 200 mg injectable contraceptive after use for a minimum period of six months or more was studied in 69 women who discontinued the method for planning pregnancy. Former users of copper intra-uterine device (CuT 200) were enrolled as a control group. Another 161 women who had discontinued NET EN due to other reasons (e.g. amenorrhoea, excessive bleeding or personal reasons) were also studied for return of fertility after ensuring that they were not using any other method of contraception and were exposed to the risk of pregnancy. The subjects from both groups were followed for a period of one year. The cumulative conception rates at one year were 72.5 and 83.6 per 100 subjects for ex-NET EN and ex-CuT 200 users who had discontinued the method for planning pregnancy and this difference was not statistically significant (P > 0.05). The median time for conception for ex-NET EN users was 7.8 months as compared to 3.7 months in ex-CuT 200 users but the cumulative conception rates at the end of one year show that future return of fertility in NET EN users does not appear to be adversely affected.

In 51 subjects who had discontinued NET EN due to amenorrhoea, the return of fertility was predictably slower and less. The return of fertility in subjects who discontinued NET EN for other reasons (e.g. excessive bleeding and other personal reasons) was similar to ex-NET EN and ex-CuT 200 users.  相似文献   

915.
916.
It is still not known how T cells are activated, which T-cell surface structures transmit activation signals, and if antigen-presenting cells possess activation structures for T cells. We have studied whether the T-cell receptor (TcR) must be engaged for T-cell activation to occur. By using membrane-incorporated monoclonal antibodies, we artificially forced T cells to bind to antigen-presenting cells in a mixed lymphocyte reaction system and thereby bypassed the need for TcR engagement and also made it possible for any surface molecule on antigen-presenting cells to deliver a stimulatory signal to the T cells. Theoretically, T cells would become polyclonally activated by this procedure. However, we found that they did not, even though they were intimately bound to the antigen-presenting cell, thus demonstrating that the TcR must participate in antigen/MHC binding in order for the T cells to become activated. This study does not exclude the possibility that antigen-presenting cells possess structures that can activate T cells.  相似文献   
917.
918.
Both abuse and new uses for benzodiazepines are reviewed. The pharmacology of benzodiazepines is summarized and statistics regarding their general use are given. The question of benzodiazepine abuse is reviewed in some detail and the question of rebound, recurrence of symptoms and physiological withdrawal is differentiated. Benzodiazepines are regarded as a very safe class of drugs and the abuse potential is felt to be negligible provided that they are prescribed for appropriate conditions and monitored carefully. The dangers of alternatives to benzodiazepines such as alcohol or barbiturates is emphasized. New uses for benzodiazepines are reviewed including the use of benzodiazepines in panic disorder, as well as an adjunct in the therapy of mania and some psychotic states. Rational prescribing of benzodiazepines is encouraged and the attitude that these are dangerous and addictive drugs is discouraged and put into perspective.  相似文献   
919.
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
  相似文献   
920.
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