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   297718篇
  免费   17348篇
  国内免费   416篇
耳鼻咽喉   4212篇
儿科学   10332篇
妇产科学   10282篇
基础医学   45270篇
口腔科学   7543篇
临床医学   24375篇
内科学   55972篇
皮肤病学   6341篇
神经病学   21199篇
特种医学   11687篇
外国民族医学   43篇
外科学   46782篇
综合类   7773篇
现状与发展   1篇
一般理论   187篇
预防医学   20021篇
眼科学   6966篇
药学   20990篇
中国医学   793篇
肿瘤学   14713篇
  2019年   2289篇
  2018年   3663篇
  2017年   2701篇
  2016年   3117篇
  2015年   3528篇
  2014年   4626篇
  2013年   7297篇
  2012年   9199篇
  2011年   9551篇
  2010年   6198篇
  2009年   5610篇
  2008年   8762篇
  2007年   9616篇
  2006年   9451篇
  2005年   9054篇
  2004年   8750篇
  2003年   8234篇
  2002年   7842篇
  2001年   13327篇
  2000年   13656篇
  1999年   11430篇
  1998年   3040篇
  1997年   2801篇
  1996年   2641篇
  1995年   2555篇
  1994年   2348篇
  1992年   8315篇
  1991年   8455篇
  1990年   8261篇
  1989年   8077篇
  1988年   7313篇
  1987年   7072篇
  1986年   6723篇
  1985年   6519篇
  1984年   4761篇
  1983年   4121篇
  1982年   2471篇
  1979年   4427篇
  1978年   3229篇
  1977年   2732篇
  1976年   2505篇
  1975年   2834篇
  1974年   3356篇
  1973年   3362篇
  1972年   3119篇
  1971年   2948篇
  1970年   2838篇
  1969年   2581篇
  1968年   2539篇
  1967年   2374篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
For the empiric management of community-acquired pneumonia, ciprofloxacin (750 mg b.i.d.) was compared with two antibiotics frequently used in this indication, i.e., amoxicillin + clavulanic acid and erythromycin. One hundred and forty-two patients were randomized in this prospective study. Among them, the 63 patients with bacteriologically documented disease were evaluated. Clinical recovery was achieved in 73.3% of patients in the ciprofloxacin group (22/30) versus 81.8% of patients in the amoxicillin + clavulanic acid or erythromycin group (27/33) (non-significant difference). Clinical failures seen with ciprofloxacin were found to be correlated with recovery of Streptococcus pneumoniae. Ciprofloxacin is effective in pneumonia but should be used only in cases where Streptococcus pneumoniae can be excluded as the causative agent.  相似文献   
992.
993.
994.
It is known that connective tissue-active peptides (CTAP) are released at sites of inflammation. Some of this material diffuses to immediately adjacent tissue and increases ground substance viscosity and fibroblast proliferation. This contributes to host protection against spread of infections and tumors. In a person with normal inflammatory reactivity, it should prevent spread of mediators and products of local inflammation. However, the host with an increased reactivity in sites of increased ground substance viscosity or who is highly reactive to dilution of tissue fluid would respond with more inflammation. A non-infectious, non-malignant process in a host with a highly reactive inflammatory or immune response could end up with peripheral spread. This could occur in any tissue but it occurs with great vigor in the skin. It could present as a peripheral extension of a local disease process, such as psoriasis, or the migration of cyclic lesions with clearing of the central area. There are over a dozen variants of peripherally spreading, ringed lesions described in the dermatologic literature. This includes erythema marginatum of rheumatic fever, erythema gyratum repens associated with cancer, and erythema annulare centrificum associated with allergic reactions to fungi. Many of the ringed dermatologic lesions have an immunologic component. They tend to be associated with inflammatory immune reactions at distant sites. Dermatologists have been gathering information on the ringed phenomenon at least since Hebra in 1854. The acute localized ground substance adaptive phenomenon is a broadly beneficial biologic response.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
995.
996.
Pachycarpine (4), the optical antipode of the lupine alkaloid (-)-sparteine (1), has been prepared from (-)-lupanine; its metabolism was studied in rats. After isolation and chromatographic purification, streochemically homogeneous (+)-(4S)-hydroxysparteine (7) was identified as the major urinary metabolite by use of mass spectrometry and high-field NMR-spectroscopy.  相似文献   
997.
Our experiences with cobalt bleomycin scintigraphy in the treatment planning of ORL tumors are described. 142 scintigrams taken from 127 patients have been examined. As is shown by our investigation, cobalt bleomycin scintigraphy is a good examination method, however, too much expenditure is needed to have the necessary data for therapy planning. To our opinion, the information obtained in oto-rhino-laryngology by an exact clinical examination is as good as that of cobalt bleomycin scintigraphy. Our treatment schemes had only to be revised in some exceptional cases.  相似文献   
998.
Amorphin--24-vicyanoside (C34H4O16(2)H2O)--in a dose of 10 mg/kg orally decreases the content of cholesterol, total lipids, atherogenic lipoproteids in the blood and organs of intact rats and rats with endogenous or ethanol hyperlipemia, inhibits the development of experimental atherosclerosis in rabbits induced by the combination of risk factors (cholesterol + glucose + hypodynamia), decreases the content of lipids in the blood and organs (especially in aorta), prevents the development of morphological manifestations of the aorta atherosclerosis.  相似文献   
999.
Tetrahydrobiopterin is an essential co-factor in the natural synthesis of dopamine. Oral tetrahydrobiopterin was given in small doses to four patients with early Parkinson's disease but had no discernible effect.  相似文献   
1000.
The long-acting analogue of luteinizing hormone releasing hormone, D-Trp6-Pro9-NEt-LHRH (LHRHa), is effective in the short-term treatment of central precocious puberty. We report the results of two to four years of LHRHa therapy in 27 children with this disorder. Secondary sex characteristics regressed in most patients. Sex steroid levels and basal and LHRH-stimulated gonadotropin levels remained suppressed compared with pretreatment values. Linear growth rates decreased from 11.0 +/- 0.8 (SEM) cm/yr before treatment to 5.7 +/- 0.4 cm/yr at two years of treatment and 3.7 +/- 0.7 cm/yr at four years of treatment. Predicted heights by the Bayley-Pinneau method increased from 156.4 +/- 2.0 cm before treatment to 162.3 +/- 2.3 cm at two years and 163.4 +/- 2.4 cm at three years. Five patients treated for four years had a mean increase in predicted height of 5.5 cm. To date no adverse effects have been observed. However, the ultimate safety of this analogue is not known. We conclude that LHRHa appears to be an effective long-term therapy for central precocious puberty.  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