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   346篇
  免费   135篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   11篇
基础医学   99篇
临床医学   39篇
内科学   67篇
皮肤病学   2篇
神经病学   23篇
特种医学   11篇
外科学   33篇
综合类   10篇
预防医学   39篇
眼科学   6篇
药学   111篇
中国医学   1篇
肿瘤学   27篇
  2019年   5篇
  2018年   6篇
  2016年   5篇
  2015年   5篇
  2013年   5篇
  2012年   14篇
  2011年   15篇
  2010年   8篇
  2008年   9篇
  2007年   8篇
  2006年   7篇
  2005年   12篇
  2004年   13篇
  2003年   22篇
  2002年   11篇
  2001年   19篇
  2000年   10篇
  1999年   7篇
  1996年   5篇
  1995年   6篇
  1993年   6篇
  1992年   11篇
  1991年   14篇
  1990年   11篇
  1989年   11篇
  1988年   8篇
  1987年   12篇
  1986年   8篇
  1985年   7篇
  1984年   10篇
  1983年   7篇
  1982年   7篇
  1981年   6篇
  1979年   6篇
  1978年   10篇
  1977年   7篇
  1976年   7篇
  1975年   9篇
  1974年   6篇
  1973年   10篇
  1972年   11篇
  1971年   7篇
  1970年   4篇
  1969年   5篇
  1968年   4篇
  1967年   5篇
  1964年   5篇
  1963年   4篇
  1960年   5篇
  1957年   4篇
排序方式: 共有481条查询结果,搜索用时 31 毫秒
1.
A new method is described to produce epithelial sheets by direct explantation of human sweat glands onto matrigel-coated millipore filters. The method is applicable to whole glands, separated coils or ducts and to normal and CF tissues. Electrogenic transport studies show that epithelia develop sodium transporting capability, even when explants are derived from secretory coils.  相似文献   
2.
1. The effects of acute or chronic morphine treatment on the changes in blood pressure and pulse rate in response to ganglionic stimulation or blockade and to vagal stimulation, and of isolated atria to field stimulation or noradrenaline, were studied. 2. In pithed rats, intravenously injected hexamethonium significantly depressed the blood pressure responses to sympathetic nerve stimulation. The ganglionic blocking effects of hexamethonium were significantly greater in chronically morphine-treated rats, but were not significantly affected by acute morphine administration in naive animals. 3. Intravenous administration of nicotine dose-dependently increased blood pressure and pulse rate. The magnitudes of these changes were not significantly affected by acute or chronic morphine pretreatment. 4. Studies with rat isolated atrial preparations revealed that the changes in atrial contractile rate and force in response to noradrenaline or field stimulation were not influenced by either acute or chronic morphine treatment. 5. Cervical vagal stimulation produced voltage- or frequency-dependent decreases in pulse rate and blood pressure. The responses were not significantly affected by chronic morphine treatment. 6. These findings suggest that the site of the changes in sympathetic function following prolonged exposure to the opiate appears to be on the preganglionic nerve fibres.  相似文献   
3.
Leukotriene (LT) receptors in the guinea-pig ileum were characterized using LTB4, LTC4, LTD4 and LTE4 and the LT antagonists FPL 55712, ICI 198615 and (+/-)SKF 104353. LTB4 was inactive but the other LTs induced concentration-related contractions. LTC4 responses differed to those induced by LTD4 or LTE4. Inhibitors of LT metabolism had no significant effects on any LT responses. LTD4 contractions were inhibited by all three antagonists but a resistant response was apparent at concentrations of ICI 198615 greater than 10(-8) M. All three antagonists were weak/inactive against LTC4. LTE4 was a partial agonist which antagonized LTD4 responses but had little or no activity against LTC4 or histamine. These results suggest that two distinct LT receptor types exist on guinea-pig ileum. One type is predominantly activated by LTD4 and is antagonized by three structurally distinct LT antagonists and the partial agonist LTE4. The second type is predominantly activated by LTC4 and is insensitive to the LT antagonists.  相似文献   
4.
5.
Circulating antigliadin antibody has been described in patients with gluten enteropathy although the prevalence varies in different studies. It has been suggested that the investigation for antigliadin antibody might be useful as a screening test. The object of the present study was to evaluate two different techniques for assaying these antibodies — an indirect immunofluorescent method and an enzyme-linked immunosorbent assay (ELISA). Antibodies were assayed in the sera of 102 patients in whom jejunal biopsies were also obtained. The specificity of both tests was greater than 95%, and the correlation between the presence of antibody and histology was significant (p < 0.005), though the sensitivity of each test was less than 70%.  相似文献   
6.
1. The sodium-dependent oxygen consumption of pieces of toad bladder (Bufo marinus) has been investigated using an oxygen electrode.2. The effect of polyvalent cations (Ca(2+), Sr(2+), Mg(2+), Eu(3+), La(3+) and Mn(2+)) on sodium-dependent oxygen consumption has been measured. All cations inhibited oxygen consumption, the order of effectiveness being Ca(2+) > Sr(2+) > Mg(2+) > Mn(2+) > Eu(3+) > La(3+).3. Treatment of bladder pieces with antidiuretic hormone (50 m-u./ml.) decreased the effectiveness of Ca(2+) and Sr(2+) as inhibitors of sodium-dependent oxygen consumption. Mn(2+), Eu(2+) and La(2+) were more effective after hormonal treatment, while the effectiveness of Mg(2+) was unaltered.4. The results have been interpreted in terms of a model in which sodium entry to the transporting mechanisms of the epithelium is controlled by Ca(2+), and in which antidiuretic hormone alters Ca(2+) binding and so affects sodium transport.  相似文献   
7.
Fear Imagery and Text Processing   总被引:7,自引:0,他引:7  
This study examined the effect of three variables held to influence heart rate response during imagery-related text processing: mode of processing, content of text, and inclusion of response information in the text. Sixty-four undergraduates imagined and silently repeated fearful and neutral sentences in a paradigm designed to allow for self-initiation of sentence processing. Fear sentences either included or did not include information about bodily responses in the image. Heart rate accelerated more during fear imagery than during neutral imagery or silent repetition of either type of sentence. Inclusion of response information in fear material did not increase heart rate response to imagery, but did affect self-report in the predicted direction. Heart rate waveform prior to the sentence tasks indicated pre-processing of fearful material. The results were discussed in relation to a bio-informational theory of imagery, which asserts that emotional imagery accesses the same centrally-mediated response program as is evoked in the target reality context, and thus occasions measurable activity in the appropriate effectors.  相似文献   
8.
One hundred one posteroanterior and 89 lateral chest radiographs were reviewed of patients with proven aberrant right subclavian artery. The patients were 17-96 years old. Three findings were noted on the posteroanterior radiograph: an oblique edge extending to the right from the aortic knob (60%); demonstration of the vessel through the lucency of the tracheal air column (43%) with sharp margins (29%) or as a tubular opacity without sharp margins (14%); and a "mass" effect at the medial right clavicular area (32%). Three findings were noted on the lateral radiograph: retrotracheal opacity (79%), aortic arch obscuration (62%), and posterior tracheal imprint (49%). Two of these findings (tubular opacity and mass effect) are reported as new observations in patients with aberrant right subclavian artery.  相似文献   
9.
HIV p24 antigenaemia and virus detection in cultures of peripheral blood lymphocytes were examined in 16 of 18 haemophiliacs infected with HIV by a single batch of Scottish National Blood Transfusion Service factor VIII concentrate. Six (38%) had p24 antigenaemia and 11 (69%) had positive lymphocyte cultures. All seven patients with serious HIV disease (CDC group IV) had positive lymphocyte cultures whereas four (57%) had p24 antigenaemia. Four of nine (44%) patients with asymptomatic HIV disease (CDC groups II and III) had positive cultures and two (22%) had p24 antigenaemia. Twenty-eight of 36 samples from the symptomatic group were HIV culture positive compared with nine of 30 samples from the asymptomatic group (P less than 0.001). None of 14 antibody negative haemophiliacs who also received the implicated batch of factor VIII had p24 antigenaemia or positive HIV cultures. The ability to detect HIV in cultured lymphocytes correlates with the clinical severity of HIV disease in this cohort.  相似文献   
10.
Two batches of heat-treated factor VIII concentrate were found to contain anti-HIV-positive plasma donations. The batches were dry-heat-treated at 68 degrees C for 2 and 24 h, respectively. No HIV seroconversions occurred in 13 susceptible haemophiliacs receiving a total of 540 bottles of these factor VIII preparations.  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