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   9233篇
  免费   650篇
  国内免费   19篇
耳鼻咽喉   83篇
儿科学   256篇
妇产科学   176篇
基础医学   1562篇
口腔科学   96篇
临床医学   1022篇
内科学   1836篇
皮肤病学   240篇
神经病学   766篇
特种医学   309篇
外科学   1000篇
综合类   95篇
一般理论   5篇
预防医学   992篇
眼科学   228篇
药学   580篇
中国医学   17篇
肿瘤学   639篇
  2023年   67篇
  2022年   83篇
  2021年   189篇
  2020年   121篇
  2019年   156篇
  2018年   222篇
  2017年   168篇
  2016年   202篇
  2015年   232篇
  2014年   283篇
  2013年   423篇
  2012年   525篇
  2011年   617篇
  2010年   344篇
  2009年   341篇
  2008年   562篇
  2007年   485篇
  2006年   523篇
  2005年   538篇
  2004年   469篇
  2003年   455篇
  2002年   409篇
  2001年   156篇
  2000年   164篇
  1999年   139篇
  1998年   99篇
  1997年   77篇
  1996年   78篇
  1995年   70篇
  1994年   69篇
  1993年   73篇
  1992年   100篇
  1991年   100篇
  1990年   79篇
  1989年   77篇
  1988年   81篇
  1987年   66篇
  1986年   64篇
  1985年   67篇
  1984年   74篇
  1983年   56篇
  1982年   41篇
  1980年   41篇
  1979年   46篇
  1978年   39篇
  1976年   38篇
  1975年   48篇
  1974年   51篇
  1973年   44篇
  1972年   34篇
排序方式: 共有9902条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
Modulation of DNA synthesis by 2,3,7,8-tetrachlorodi-benzo-p-dioxin(TCDD) was studied in primary cultures of hepatocytes and inrat liver epithelial cells (WB-F344) to develop models for studieson the interactions between the activated Ah receptor and cellulargrowth control. In hepatocytes TCDD either positively or negativelymodulated EGF-stimulated DNA synthesis. In the presence of ethlnylestradiol10–12 M TCDD moderately increased EGF-stimulated DNA synthyesis(  相似文献   
15.
Plasma protein fraction (PPF) contaminated by factor XII active fragment (XIIf) may cause hypotensive reactions when infused to patients. This study was planned to assess in conscious normotensive rats whether the blood pressure response to the factor XIIf is mediated by an activation of the plasma kallikrein-kinin system or by stimulation of prostaglandin synthesis. To test whether the factor XIIf-induced blood pressure fall is due partially to an enhanced generation of vasodilating prostaglandins, the blood pressure effect of XIIf (1 microgram i.v.) was investigated 15 min after treatment with indomethacin (5 mg i.v.), an inhibitor of cyclo-oxygenase. Factor XIIf reduced mean blood pressure similarly in indomethacin- and vehicle-treated rats (-23 +/- 4 mmHg, n = 5, and -23 +/- 5 mmHg, n = 4, respectively). Other rats received factor XIIf 15 min after depletion of circulating prekallikrein by the administration of dextran sulfate. Thirty minutes after a 0.25 mg i.v. dose of this agent, plasma prekallikrein activity averaged 0.12 +/- 0.015 mumol/min/ml (n = 6) as compared to 2.48 +/- 0.31 mumol/min/ml in control rats (n = 4, P less than .001). Factor XIIf decreased mean blood pressure by only 4 +/- 2 mm Hg in rats pretreated with dextran sulfate. Thus, it was possible to blunt the acute hypotensive effect of factor XIIf by depleting circulating prekallikrein, but not by inhibiting prostaglandin production. This strongly suggests that the blood pressure effects of factor XIIf is mediated by a stimulation of the plasma kallikrein-kinin system.  相似文献   
16.
beta/A4, a peptide that forms the extracellular amyloid fibrils of Alzheimer senile plaques, has also been proposed to be a component of Alzheimer paired helical filaments (PHFs). We compared BR88, an antiserum to amino acids 1-12 of beta/A4, with BR126, an antiserum to the sequence SEKLDFKDRVQS in tau protein, since tau protein is the only confirmed component of PHFs. In enzyme-linked immunosorbent assays (ELISAs), both antibodies reacted with pronase-treated PHFs better after PHFs were treated with guanidine. tau protein shares no sequence homology with beta/A4. Nevertheless, BR88 cross-reacted with human recombinant tau isoforms by ELISA and Western blot analysis with potencies comparable to those for anti-tau antibodies. BR88 reacted with a beta/A4 peptide as well on a molar basis as with tau protein and showed some reactivity to the tubulin-binding region of tau protein. In conclusion, the beta/A4 antiserum BR88 cross-reacts with tau protein, possibly explaining its reactivity with PHFs.  相似文献   
17.
18.
Thirty inpatients with somatoform disorders were examined with the structured clinical interview SCID for psychiatric lifetime diagnosis. In the present diagnoses, we found a concordance of 63% for somatoform and affective disorders and the lifetime comorbidity of both disorders was 87%. Additionally, patients with somatoform disorders frequently had a history of other psychiatric disorders (for example, anxiety disorders, 40%). For 73% of patients with somatoform disorders and a history of affective disorders, the onset of the somatoform disorder was prior to the onset of another psychiatric disorder. The time interval between the onsets of somatoform disorders and affective disorders was greater than 1 year for most patients; for 46% of the patients with a history of both disorders, the time interval between the two disorders was more than 5 years. The course of illness for somatoform and affective disorders was quite different; while affective disorders tended to episodic periods with interim remissions, the somatoform disorders usually showed long, chronic courses (mean duration of the current somatoform disorder was 11.9 years). Finally, the Symptom Check List SCL-90R demonstrated good discrimination between patients with affective and anxiety disorders. However, the SCL-90R failed to discriminate patients with somatoform disorders from affective- and anxiety-disordered subjects. Therefore, the development of other psychometric scales is necessary for the evaluation of patients with somatoform disorders.  相似文献   
19.
This final issue of the series "Emergency and intensive care therapy for hematooncological diseases" reviews cytopenias in intensive care patients who do not offer any oncological or haematological problems in their medical history. Anaemia is a very common problem in the intensive care setting. We highlight aetiological aspects of anaemia in critically ill patients and discuss therapeutical options like substitution of blood and application of erythropoietin, respectively. The second paragraph focuses on leukocytopenia and agranulocytosis, their causation and therapy and among other things the application of G-CSF (Granulocyte colony-stimulating factor). Last but not least, we deal with thrombocytopenia, especially heparin-induced thrombocytopenia.  相似文献   
20.
Gluteal and lower extremity hypoplasia with ipsilateral toe brachysyndactyly were noted in a 23-year-old woman similarly affected to the only previously reported case of the lower extremity counterpart of Poland sequence. Since no neurological deficit was found, and electromyographic and nerve conduction studies in the affected limb were normal, we propose a vascular origin which would involve the external iliac artery supply analogous to the subclavian artery supply disruption in the upper extremity Poland sequence.  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