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   2636096篇
  免费   209825篇
  国内免费   4904篇
耳鼻咽喉   35858篇
儿科学   87652篇
妇产科学   74928篇
基础医学   374352篇
口腔科学   75659篇
临床医学   236594篇
内科学   515839篇
皮肤病学   58631篇
神经病学   216094篇
特种医学   103148篇
外国民族医学   897篇
外科学   395604篇
综合类   64842篇
现状与发展   6篇
一般理论   970篇
预防医学   207491篇
眼科学   60943篇
药学   192694篇
  3篇
中国医学   5479篇
肿瘤学   143141篇
  2018年   27461篇
  2017年   21100篇
  2016年   23780篇
  2015年   27045篇
  2014年   37965篇
  2013年   57354篇
  2012年   77502篇
  2011年   81896篇
  2010年   48367篇
  2009年   46218篇
  2008年   77026篇
  2007年   81453篇
  2006年   82711篇
  2005年   80249篇
  2004年   77815篇
  2003年   74430篇
  2002年   72353篇
  2001年   125916篇
  2000年   129554篇
  1999年   108859篇
  1998年   30525篇
  1997年   27640篇
  1996年   27575篇
  1995年   26510篇
  1994年   24524篇
  1993年   23168篇
  1992年   86290篇
  1991年   83173篇
  1990年   80656篇
  1989年   77517篇
  1988年   71832篇
  1987年   70497篇
  1986年   66649篇
  1985年   63918篇
  1984年   48307篇
  1983年   41337篇
  1982年   24744篇
  1981年   22053篇
  1979年   44755篇
  1978年   31276篇
  1977年   26322篇
  1976年   24789篇
  1975年   25753篇
  1974年   31479篇
  1973年   30403篇
  1972年   28072篇
  1971年   26132篇
  1970年   24433篇
  1969年   22759篇
  1968年   21062篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
151.
152.
Landgraf  R. 《Der Diabetologe》2006,2(1):S5-S8
NAFDM, the National Action Forum for Diabetes Mellitus, is an umbrella organisation for the leading diabetes organisations in Germany. Since its foundation at the end of 2004, NAFDM has brought together the activities of these organisations, which up to now were frequently working independently of each other, under a single ‘roof’. Supported by a central coordination unit, three project groups work successfully on the topics scientific research and healthcare research, patient care and prevention. Activities and results are shared and thus integrated into the network. The working groups are supported by NAFDM’s medical and health-policy steering groups. Apart from a number of successful events, two key publications have meanwhile come out: one on the status of prevention and one analysing the healthcare situation for diabetics in Germany. All people interested in diabetology are invited to join in and work with the NAFDM.  相似文献   
153.
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.  相似文献   
154.

Background  

The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period.  相似文献   
155.
On September 11, 2001 two hijacked airplanes struck the Twin Towers at the World Trade Center in New York City. All of the remains (19,915) were examined by the Office of Chief Medical Examiner (OCME) of New York City. The major goals of the OCME were to accurately identify the decedents and to promptly issue death certificates. As of September 2005, there were 1594 identifications of a total of 2749 people reported missing. Of these, 976 were identified by a single means, which included DNA analysis in 852 of the victims. Use of legal statues can assist in the timely issuance of death certificates in mass fatalities, which benefit surviving family members. DNA analysis markedly improves the ability to identify remains and has become the standard method for identification in these types of disasters. Certain postmortem tissue samples are better suited for DNA analysis and yield better results than others.  相似文献   
156.
We study the image formation of vibro-acoustography systems based on a concave sector array transducer taking into account depth-of-field effects. The system point-spread function (PSF) is defined in terms of the acoustic emission of a point-target in response to the dynamic radiation stress of ultrasound. The PSF on the focal plane and the axis of the transducer are presented. To extend the obtained PSF to the 3D-space, we assume it is a separable function in the axial direction and the focal plane of the transducer. In this model, an image is formed through the 3D convolution of the PSF with an object function. Experimental vibro-acoustography images of a breast phantom with lesion-like inclusions were compared with simulated images. Results show that the experimental images are in good agreement with the proposed model.  相似文献   
157.
Summary We present a case of blindness and Anton’s syndrome in a psychiatric patient with late diagnosis of a giant frontal meningioma. The criteria for advanced diagnostic imaging in the psychiatric population are discussed. We conclude that MR or CT scan is indicated in psychiatric in-patients who fail to improve with standard psychiatric treatment. This strategy should be submitted to a cost-benefit analysis.  相似文献   
158.
159.
BACKGROUND: The laparoscopic resection of rectal cancer shows morbidity and oncological safety comparable to the open approach, but morbidity increases after conversion to open resection. No oncological long-term results are available for the latter patients. METHODS: From 01/01/2000-31/12/2002, patients with curatively resected rectal cancer enrolled in a observational study were evaluated for morbidity, mortality, tumor- and local recurrence rate, paying attention to patients with conversion from laparoscopic to open resection. RESULTS: 237 (3.3%) of 7,189 patients underwent laparoscopic resection (ITT). These patients showed significantly more T1/2 tumors (P<0.001) in earlier UICC stages (P<0.001) than open resected patients. 35 (14.8%) of 237 laparoscopic procedures were converted. Compared with patients receiving complete laparoscopic or open resection, these patients showed significantly higher frequencies of intraoperative (P<0.001) and general postoperative complications (P=0.003) as well as the highest overall morbidity (P=0.031). After a median follow-up of 30.1 months, the highest 5-year local recurrence rate was found in the converted group (16.0%). The laparoscopically resected patients showed a local recurrence rate of 3.3%, patients with open resection of 12.4% (P=0.082). The disease-free survival rate did not differ between the groups (P=0.585). CONCLUSION: Laparoscopic resection of rectal cancer provides oncological results similar to open resection. After conversion, the short and oncological long-term outcomes were worse. Considering a conversion rate of 15%, only a strict indication for the laparoscopic approach can be allowed, and laparoscopic resection should be performed at centers.  相似文献   
160.
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