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   31800篇
  免费   147篇
  国内免费   25篇
耳鼻咽喉   300篇
儿科学   1749篇
妇产科学   937篇
基础医学   2821篇
口腔科学   1564篇
临床医学   1548篇
内科学   7962篇
皮肤病学   718篇
神经病学   2079篇
特种医学   794篇
外科学   6684篇
综合类   534篇
预防医学   1493篇
眼科学   616篇
药学   1164篇
  4篇
中国医学   80篇
肿瘤学   925篇
  2024年   3篇
  2023年   39篇
  2022年   109篇
  2021年   480篇
  2020年   89篇
  2019年   5992篇
  2018年   4460篇
  2017年   2104篇
  2016年   58篇
  2015年   60篇
  2014年   195篇
  2013年   163篇
  2012年   167篇
  2011年   208篇
  2010年   158篇
  2009年   162篇
  2008年   172篇
  2007年   141篇
  2006年   94篇
  2005年   57篇
  2004年   48篇
  2003年   41篇
  2002年   33篇
  2001年   41篇
  2000年   56篇
  1999年   34篇
  1998年   11篇
  1997年   8篇
  1996年   18篇
  1995年   18篇
  1994年   27篇
  1993年   2篇
  1992年   6篇
  1991年   6篇
  1990年   4篇
  1988年   8篇
  1985年   1447篇
  1984年   2268篇
  1983年   1577篇
  1982年   1697篇
  1981年   1619篇
  1980年   1396篇
  1979年   1384篇
  1978年   1143篇
  1977年   870篇
  1976年   1023篇
  1975年   837篇
  1974年   747篇
  1973年   685篇
  1972年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
We have studied a 50-year-old white man with chronic urticaria and angioedema who has responded to treatment with cimetidine alone for over 2 yr. In a double-blind, placebo-controlled study, cimetidine alone was at least as effective as chlorpheniramine in relief of urticaria and angioedema. Additionally, cimetidine significantly inhibited (p less than 0.01) the wheal response to histamine when it was compared to placebo. The inhibition of wheal response to histamine by cimetidine was significantly higher (p less than 0.05) than chlorpheniramine. The presence of predominantly H2- rather than H1-histamine receptors in the cutaneous blood vessels may be responsible for the therapeutic effects of cimetidine in this patient.  相似文献   
102.
103.
Aqueous extracts of tree pollen were partially purified and polymerized with methods previously established for preparation of ragweed and grass polymers. The polymerized tree preparations were antigenic as demonstrated by ability to elicit immediate-type skin reactivity in humans and to induce an immune response in rabbits. The polymerized tree antigen was 100- to 10,000-fold less skin reactive than monomer tree antigen in tree pollen-sensitive patients but both preparations had similar antigenicity in rabbits. These results demonstrate that polymerized tree antigens can be prepared and should have the therapeutic potential already demonstrated for polymerized ragweed preparations.  相似文献   
104.
A family history study of second-degree relatives of 19 patients with anxiety neurosis (panic disorder) and 19 controls showed a morbidity risk of 9.5% among the former compared with 1.4% among the latter. These risks were approximately half those found among first-degree relatives. Female relatives were at higher risk for anxiety neurosis. The risk for other psychiatric illnesses did not differ between the relatives of anxiety neurosis and controls.  相似文献   
105.
Arterial spasm was induced by application of calcium chloride to the adventitial surface of the rabbit common carotid artery in vivo. Sodium chloride (NaCl) was applied to the contralateral vessel as control. Vessels were fixed in situ by intravascular perfusion after 15 min, 1 hr, or 24 hr and prepared for light and scanning electron microscopy (SEM). With SEM, the luminal surface at the site of calcium application showed severe longitudinal folding accompanied by endothelial desquamation with extensive platelet deposition on exposed subendothelium. The luminal cross-sectional area was reduced by 53 +/- 19.5% after 15 min and by 44 +/- 12% after 1 hr as compared with the contralateral control. Furthermore, the luminal area at the site of calcium application was found to be reduced by 42 +/- 8% after 1 hr when compared with segments of the same vessel distal to the site of calcium application. Blood flow rate, as measured by electromagnetic flow probe, was not reduced. Vessels examined after 24 hr showed a significant increase in luminal cross-sectional area as compared with contralateral control vessels (136 +/- 70%). Control vessels (NaCl) showed no significant change in luminal cross-sectional area and no endothelial desquamation or platelet deposition after 15 min, 1 hr, or 24 hr. Examination of histologic sections showed calcium precipitation within the attached thrombus after 15 min with calcium deposits also adherent to the adjacent luminal aspect of the internal elastic lamina (IEL). By 24 hr, this precipitation extended throughout the media. Marked deposition of leukocytes was seen after 24 hr which showed a preferential attachment for areas of endothelial damage and discontinuity of IEL.  相似文献   
106.
A 17-year-old woman with rheumatic carditis underwent endomyocardial biopsy both prior to and following treatment with prednisone and aspirin. Frozen sections from the endomyocardial biopsy specimens were studied with monoclonal antibodies by an indirect immunofluorescence technique to define the composition of the inflammatory infiltrate in the myocardium and to determine whether the composition of the infiltrate is distinctive and diagnostically useful. The specimen from the initial biopsy contained a heterogeneous infiltrate composed of T lymphocytes, macrophages, B lymphocytes, and mast cells. T lymphocytes predominated, and the ratio of T-helper to T-cytotoxic/suppressor cells was 2.0. Following treatment the overall cellularity of the infiltrate was diminished, but the infiltrate remained heterogeneous; T cells predominated, and the T-helper to T-cytotoxic/suppressor ratio was reversed, to 0.59. The composition of the inflammatory infiltrate in this case of rheumatic carditis distinguishes it immunologically from other "idiopathic," presumably virus-associated, forms of myocarditis.  相似文献   
107.
108.
109.
Preliminary experiments indicated that solutions of aspirin (ASA) in buffered saline, pH 7.35, did not significantly change nasal airways resistance (NAR) when 0.1 ml of solution containing 22.5 mg (or less) per deciliter was sprayed into each nostril. Subsequently it was shown that this quantity of ASA administered intranasally did not significantly change NAR responses 15 min later to intranasal administration of increasing concentrations of histamine, methacholine, or an irritant (NH3 gas). However, the same atopic subjects demonstrated significantly decreased responses to intranasal challenge with short ragweed extract (SRW) after intranasal ASA. In addition, prior oral administration of ASA, Na salicylate, and indomethacin significantly inhibited nasal challenge responses to SRW in sensitive subjects under controlled conditions.  相似文献   
110.
Sera of 86 patients clinically sensitive to foods were tested by passive sensitization of human and/or monkey lung (127 tests) and the radioallergosorbent test (RAST) (72 tests), using whole-food antigens; the results were compared with skin (prick) testing. Results of the prick test correlated with history in 76% of cases; lung sensitization correlated with history in 37% and with prick test in 57%; and RAST correlated with history in 54% and prick test in 72%. It is concluded that a very large percentage of adverse reactions to foods are IgE-mediated. The prick test is of use in diagnosis, particularly when combined with RAST; the lung sensitization test is technically impractical and not a reliable indicator. The best diagnostic method is careful history with food challenge and withdrawal and rechallenge; the latter is safe except in patients with a history of violent reaction.  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