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   2554367篇
  免费   200395篇
  国内免费   3973篇
耳鼻咽喉   36382篇
儿科学   86815篇
妇产科学   72267篇
基础医学   363477篇
口腔科学   72920篇
临床医学   226374篇
内科学   499523篇
皮肤病学   54920篇
神经病学   204978篇
特种医学   101953篇
外国民族医学   1064篇
外科学   388425篇
综合类   60122篇
现状与发展   4篇
一般理论   894篇
预防医学   197548篇
眼科学   58655篇
药学   191833篇
  5篇
中国医学   4749篇
肿瘤学   135827篇
  2018年   24900篇
  2016年   21209篇
  2015年   24285篇
  2014年   33759篇
  2013年   51806篇
  2012年   70350篇
  2011年   74471篇
  2010年   44336篇
  2009年   42181篇
  2008年   71334篇
  2007年   75689篇
  2006年   76602篇
  2005年   74567篇
  2004年   73053篇
  2003年   70198篇
  2002年   68834篇
  2001年   119816篇
  2000年   124302篇
  1999年   105545篇
  1998年   29060篇
  1997年   26318篇
  1996年   26632篇
  1995年   25683篇
  1994年   24229篇
  1993年   22694篇
  1992年   86136篇
  1991年   84020篇
  1990年   82217篇
  1989年   78880篇
  1988年   73155篇
  1987年   72057篇
  1986年   68028篇
  1985年   65565篇
  1984年   49147篇
  1983年   42128篇
  1982年   24722篇
  1981年   22230篇
  1980年   20545篇
  1979年   46079篇
  1978年   32146篇
  1977年   27094篇
  1976年   25510篇
  1975年   27206篇
  1974年   32764篇
  1973年   31566篇
  1972年   29046篇
  1971年   26926篇
  1970年   25019篇
  1969年   23236篇
  1968年   21238篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
33.
Bernard–Soulier syndrome (BSS) is a rare autosomal recessively inherited bleeding disorder. Pregnancy in patients with BSS is characterized by ante‐, intra‐, or postpartum haemorrhage, which may be delayed and severe. There is no consensus in the management of BSS in pregnancy and so far only 16 pregnancies in nine patients have been described. We report a further three pregnancies in two women with the syndrome. We also outline our management of pregnant patients with BSS.  相似文献   
34.
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   
35.
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   
36.
Conclusion  Several quality-control measures take place before (patient and camera preparation) and during SPECT acquisition to achieve high-quality images. Not uncommonly, technologists and physicians are left with suboptimal images that have to be addressed to reach the “right answer” for patient diagnosis and hence management. In many cases patients may be reimaged, especially if the problem is detected early, but in other cases either the patient has left the nuclear laboratory or there is an inevitable problem that, even with reimaging, will not be resolved. In these situations the technologist and physician have to seek the available techniques to obtain the best images possible. These resources are discussed in this issue as an aid in quality control to obtain the best possible images.  相似文献   
37.
38.
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   
39.
40.
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   
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