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   2223193篇
  免费   166513篇
  国内免费   7370篇
耳鼻咽喉   29693篇
儿科学   71208篇
妇产科学   60012篇
基础医学   308653篇
口腔科学   62022篇
临床医学   199639篇
内科学   441109篇
皮肤病学   52171篇
神经病学   177217篇
特种医学   90468篇
外国民族医学   472篇
外科学   343616篇
综合类   49380篇
现状与发展   3篇
一般理论   656篇
预防医学   168870篇
眼科学   48835篇
药学   165127篇
  10篇
中国医学   4553篇
肿瘤学   123362篇
  2018年   22473篇
  2017年   17783篇
  2016年   20947篇
  2015年   23333篇
  2014年   32252篇
  2013年   47926篇
  2012年   61214篇
  2011年   65379篇
  2010年   39958篇
  2009年   38491篇
  2008年   61040篇
  2007年   65192篇
  2006年   66617篇
  2005年   63928篇
  2004年   61201篇
  2003年   59385篇
  2002年   56906篇
  2001年   112373篇
  2000年   115735篇
  1999年   96627篇
  1998年   26871篇
  1997年   23894篇
  1996年   24669篇
  1995年   24267篇
  1994年   22446篇
  1993年   21134篇
  1992年   77188篇
  1991年   74842篇
  1990年   72646篇
  1989年   69741篇
  1988年   63918篇
  1987年   62623篇
  1986年   59040篇
  1985年   56433篇
  1984年   42061篇
  1983年   35390篇
  1982年   21067篇
  1981年   18654篇
  1980年   17654篇
  1979年   37833篇
  1978年   26606篇
  1977年   23008篇
  1976年   20661篇
  1975年   22323篇
  1974年   26107篇
  1973年   25096篇
  1972年   23498篇
  1971年   21842篇
  1970年   20005篇
  1969年   18999篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Interest in inguinal hernia surgery has increased significantly with the introduction of new operating techniques during the past decade. This multicenter study compared short-term results in patients treated by the laparoscopic transabdominal preperitoneal patch technique (TAPP; n=518) and the Shouldice technique (n=524). We evaluated demographics, operative data, complications, hospital stay, postoperative pain, use of analgesics, functional status, sick leave, and complaints up to 3 months postoperatively. The median operating time was shorter in the Shouldice group (55 vs. 65 min), but there were no significant differences in complication rates, and major complications were rare. The hospital stay was 1 day or less in over 98% of cases in both groups, but more operations were performed on outpatient basis in the Shouldice group. In the TAPP group postoperative pain and analgesic consumption were less, postoperative functional status was better, and sick leave was shorter (10 vs. 14 days). These results show that the two methods are equally safe and have few major complications. The TAPP operation is associated with less postoperative pain, better postoperative functional status, and shorter sick leave, but at the price of a longer operating time. Electronic Publication  相似文献   
992.
993.
The carcinogenicity of dextran and 3 kinds of dextran sulfate sodium with different molecular weights and almost the same sulfur content were compared in ACI rats. Dextran sulfate sodium of molecular weight 54,000 showed a strong carcinogenic activity when it was given orally as 2.5% diet, whereas dextran sulfate sodium of molecular weight 520,000 and 9500 and dextran showed no significant carcinogenicity, i.e. the peak of carcinogenic activity of dextran sulfate sodium appeared at molecular weight 54,000, and dextran sulfates with larger or smaller molecular weights had no carcinogenic activity.  相似文献   
994.
995.
Salmus is a product of Salvia sclarea technology that is widely used in balneary practice. It is established that the analytical characteristics of salmus substance, as stipulated in the temporal pharmacopoeial article VFS 42-1530-85, are not objective and should not be used for evaluating the quality of the ready-to-use preparation and for monitoring the process of its manufacturing. TLC data show that salmus contains all components of sage oil (Russian State Standard GOST 3171-76) except for linalyl acetate. Qualitative specific color reactions on Silufol TLC plates showed for the first time the presence of flavonoids such as kaempferol, quercetin, juglanin, quercitrin, and rungioside and revealed one previously unknown substance, probably, of a flavonoid nature. The TLC data also showed the presence of condensed tannins and chlorophylls. It is suggested to perform quantitative analysis and identification of biologically active substances in salmus using methods for determining the content of reducing sugars (carbohydrates) and oxidizable components. New procedures for determining the sum of essential oils and flavonoids using the total content of extractable components have been developed and verified. It is suggested that these substances are among the main therapeutic components of salmus. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 8, pp. 33 – 36, August, 2005.  相似文献   
996.
Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.  相似文献   
997.
Esophageal pH monitoring is the accepted standard for the investigation of gastroesophageal reflux (GER) in adults. A postal questionnaire was sent to 912 United Kingdom paediatric physicians & surgeons. Five hundred forty-seven (61%) replied, with 124 (22.7%) currently using the technique, mostly in conjunction with barium swallow and/or esophagoscopy. The use of pH monitoring to quantify GER was also accepted in principal as being the best determinant of reflux by a further 186 (34%), but as yet was unavailable in their hospitals. Pediatricians were also questioned as to their management of children with GER. The majority were treated medically with a variety of antireflux medication, with only 237 (42%) referring cases for surgery.  相似文献   
998.
999.
1000.
On the basis of data showing a bimodal distribution of values for extracellular pH (pHe), and a discontinuous delta PCO2/delta lactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured delta pHe during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but delta pHe varied linearly with lactate content. Because we have also failed to record a discontinuous delta PCO2/delta lactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.  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