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   101944篇
  免费   5537篇
  国内免费   311篇
耳鼻咽喉   1164篇
儿科学   2291篇
妇产科学   2195篇
基础医学   13615篇
口腔科学   3832篇
临床医学   7856篇
内科学   25378篇
皮肤病学   2445篇
神经病学   8743篇
特种医学   2316篇
外科学   14005篇
综合类   509篇
一般理论   35篇
预防医学   8686篇
眼科学   1842篇
药学   6718篇
中国医学   391篇
肿瘤学   5771篇
  2024年   63篇
  2023年   654篇
  2022年   708篇
  2021年   2053篇
  2020年   1135篇
  2019年   2036篇
  2018年   3174篇
  2017年   2012篇
  2016年   2103篇
  2015年   2770篇
  2014年   3219篇
  2013年   4419篇
  2012年   8716篇
  2011年   8986篇
  2010年   4299篇
  2009年   3331篇
  2008年   7490篇
  2007年   7718篇
  2006年   7563篇
  2005年   7152篇
  2004年   6545篇
  2003年   6039篇
  2002年   5641篇
  2001年   1810篇
  2000年   2276篇
  1999年   1244篇
  1998年   459篇
  1997年   345篇
  1996年   347篇
  1995年   306篇
  1994年   245篇
  1993年   220篇
  1992年   227篇
  1991年   190篇
  1990年   138篇
  1989年   135篇
  1988年   108篇
  1987年   94篇
  1986年   97篇
  1985年   125篇
  1984年   149篇
  1983年   116篇
  1982年   141篇
  1981年   126篇
  1980年   129篇
  1979年   68篇
  1978年   72篇
  1977年   68篇
  1976年   56篇
  1974年   67篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
101.
102.
103.
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.  相似文献   
104.
BACKGROUND: Randomized studies demonstrate that laparoscopic appendectomy yields better results compared with open techniques. We sought to identify factors that determine an extended hospital stay among patients undergoing laparoscopic appendectomy. METHODS: This was a prospective study including 669 patients undergoing laparoscopic appendectomy. We analyzed variables that can predict the length of hospital stay. RESULTS: Of 669 patients undergoing laparoscopic appendectomy, 141 stayed in the hospital for > or = 5 days (Group 1), and 97 stayed in the hospital for < or = 1 day after surgery (Group 2). The univariate analysis demonstrated that fever (P<0.0001), nausea and vomiting (P=0.060), leukocytosis (P<0.0001), gangrened or perforated intraoperative appearance of the appendix (P<0.0001), and appendix position behind the ileocecal junction (P<0.001) were related to a longer hospital stay. The multivariate analysis through logistical regression showed that the factors independently and significantly associated with an extended hospital stay were presurgical fever, appendix position behind the ileocecal junction, and intraoperative gangrened or perforated appearance of the appendix. CONCLUSION: Fever, appearance, and position of the appendix are factors related to an extended hospital stay.  相似文献   
105.
The present study was designed to examine the effects of a >30kDa fraction of medium conditioned for 2 days by adult rat seminiferoustubules on inhibin secretion by cultured tubules, and on spermatogenesisand fertility of male rats. Inhibin secretion was assayed byadding the >30 kDa fraction to 5 cm segments of adult ratseminiferous tubules and measuring inhibin by radioimmunoassayat 2 day intervals. Fertility was assayed by injecting malerats daily for up to 45 days with the >30 kDa fraction andthen mating them with a proestrus female, or by injecting for15 days and mating them with two female rats. The assay usedto evaluate the in-vivo effect of the >30 kDa fraction onthe testis involved an assessment of frequencies of seminiferoustubule stages scored by transillumination on intact tubules.The addition of the >30 kDa fraction to the adult rat seminiferoustubules cultured for 2 days resulted in an inhibition of inhibinsecretion into the medium. This effect was reversed when thefraction was removed and changed with fresh medium and culturedfor a further 4 days. The >30 kDa fraction administered i.p.to adult male rats resulted in a low fertilization rate comparedto control rats (67%) (P < 0.05). The assessment of frequenciesof seminiferous tubule stages scored by transillumination showedan increased frequency of stage VI and decreased frequency ofstages VII and VIII after treatment. The results of the presentstudy provide additional evidence that local regulation of Sertolicell function is mediated by a >30 kDa component or componentssecreted by adult seminiferous tubules which could arrest spermatogenesis.  相似文献   
106.
107.
Percutaneous embolization of large portosystemic collaterals was performed in three patients following placement of a transjugular intrahepatic portosystemic shunt in order to improve hepatopetal portal flow. Improved hepatic portal perfusion was achieved in these cases, thereby theoretically reducing the risk of chronic hepatic encephalopathy.  相似文献   
108.
Paclitaxel is an antineoplastic agent derived from the bark of the Pacific yew tree that has activity against many tumors including breast and ovarian carcinomas. In the past, its extravasation quality has been considered to be a local irritant; however, recent reports suggest that the agent may be a vesicant. A patient experienced a delayed vesicant reaction to a paclitaxel extravasation that resulted in severe necrosis. No acute symptoms were reported at the time of extravasation from the 24-hour peripheral paclitaxel infusion. However, on day 11 the patient complained of severe and progressive pain at the site of extravasation. The site was erythematous and had areas of central necrosis requiring debridement and closure by a plastic surgeon. Because paclitaxel possesses vesicant characteristics, health care professionals should be aware of its potential extravasation hazard. Prolonged peripheral infusions should be avoided or administered with extreme caution.  相似文献   
109.
We performed single fiber electromyography (SFEMG) in the superior rectus and levator palpebralis (SR-LP) muscles of 17 patients with pure ocular myasthenia gravis (MG) and 9 controls. Thirteen patients were also assessed with SFEMG in the orbicularis oculi (OO) muscle. All the MG patients but none of the control subjects showed abnormal SFEMG jitter in the SR-LP muscles. On the other hand, only 62% of the MG patients had abnormal SFEMG jitter in the OO muscle. The procedure was well tolerated by the patients, and complications were minor. We conclude that SFEMG of the SR–LP muscles is a safe and highly sensitive technique for the diagnosis of ocular MG. © 1995 John Wiley & Sons, Inc.  相似文献   
110.
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