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   2805篇
  免费   140篇
  国内免费   7篇
耳鼻咽喉   35篇
儿科学   61篇
妇产科学   31篇
基础医学   384篇
口腔科学   46篇
临床医学   484篇
内科学   421篇
皮肤病学   16篇
神经病学   510篇
特种医学   101篇
外科学   388篇
综合类   15篇
预防医学   132篇
眼科学   12篇
药学   128篇
中国医学   21篇
肿瘤学   167篇
  2022年   17篇
  2021年   41篇
  2020年   25篇
  2019年   28篇
  2018年   37篇
  2017年   54篇
  2016年   57篇
  2015年   72篇
  2014年   81篇
  2013年   109篇
  2012年   141篇
  2011年   158篇
  2010年   90篇
  2009年   94篇
  2008年   146篇
  2007年   142篇
  2006年   129篇
  2005年   158篇
  2004年   128篇
  2003年   101篇
  2002年   103篇
  2001年   99篇
  2000年   88篇
  1999年   73篇
  1998年   24篇
  1997年   22篇
  1996年   16篇
  1992年   53篇
  1991年   40篇
  1990年   43篇
  1989年   41篇
  1988年   37篇
  1987年   35篇
  1986年   27篇
  1985年   26篇
  1984年   21篇
  1983年   21篇
  1982年   13篇
  1981年   12篇
  1979年   20篇
  1978年   13篇
  1977年   16篇
  1975年   12篇
  1974年   19篇
  1973年   24篇
  1970年   13篇
  1969年   15篇
  1968年   12篇
  1965年   12篇
  1957年   13篇
排序方式: 共有2952条查询结果,搜索用时 0 毫秒
11.
    
Sans résumé  相似文献   
12.
Patient on-off diaries are used in clinical trials, but a method to assure agreement between patient and examiner has never been developed. We tested whether a patient-teaching tape increased the rate of agreement between patient diary ratings and simultaneous neurologic assessment by a trained professional. A total of 32 consecutive patients who had Parkinson's disease with motor fluctuations independently completed a 4-h on-off diary (nine ratings) at the same time as an examiner. Those with <80% agreement with the examiner (n = 20) were randomized to view either a training tape that showed motor fluctuations (experimental group) or another videotape of general patient educational material (control group). All patients then underwent the same 4-h assessment of motor fluctuations. To test for long-term retention, they returned 1 month later and, without reviewing the videotape, underwent a final 4-h correlation assessment. After the training tape, the experimental group showed significant improvement, whereas the control group showed no improvement. Furthermore, another month later, the improvement in the experimental group was retained. Based on these findings, we suggest that future clinical trials assessing motor fluctuations incorporate this tape into their basic methodology.  相似文献   
13.
14.
15.
Human brucellosis has become a rare disease in Germany since the eradication of bovine and ovine/caprine brucellosis in this country. Therefore, most physicians are unfamiliar with the illnesses clinical presentation, diagnostic tools, and therapeutic strategies. This retrospective study was carried out to evaluate the epidemiological, clinical, and laboratory features of human brucellosis in Germany in the years 2002 and 2003. Thirty-one bacterial isolates from 30 patients sent to the German national reference laboratory were characterized using the genus-specific bcsp31 real-time PCR, the species-specific AMOS-PCR, and standard microbiological methods for the detection and identification of Brucella spp. The medical records of all patients with bacteriologically confirmed brucellosis were evaluated. All 31 isolates proved to be Brucella (30 Brucella melitensis and 1 Brucella suis). Most of the brucellosis patients were infected in endemic countries while visiting friends and relatives during their summer holidays. One case of laboratory-acquired infection was identified. Brucellosis was transmitted mainly by the consumption of contaminated unpasteurized milk or cheese from goats and sheep. The patients presented primarily with flu-like symptoms, i.e. fever, chills, sweating, headaches, arthralgia, and myalgia. In most cases, however, symptoms and signs of focal complications, e.g. spondylitis, endocarditis, and meningoencephalitis, predominated. The rate of complications was much higher than that in endemic countries, presumably as a result of diagnostic delay due to a low index of suspicion. In summary, physicians in nonendemic countries such as Germany must be aware of brucellosis being a possible cause of fever of unknown origin in immigrants and tourists travelling from endemic countries.  相似文献   
16.
Journal of Molecular Medicine - An vier verschiedenen Escherichia Colistämmen, die alle mehr oder weniger starke Erythromycin-Resistenz aufwiesen, wurde der Einfluß von Erythromycin in...  相似文献   
17.
1. The technique of single fibre dissection has been used to study the warm and cold thermoreceptors in the rat scrotum. 2. The warm receptors showed dynamic activity during increases of scrotal temperature and static activity when temperature was constant. The static activity/temperature curve was bell-shaped, with minima at 31 and 45 degrees C and a peak at 42 degrees C. 3. The cold receptors also showed dynamic and static responses to reductions of temperature. At steady temperatures the impulses from some receptors were grouped in bursts. The number of impulses in each burst increased from zero at 30 degrees C to four at 20 degrees C.  相似文献   
18.
Summary Afferent single fiber impulses were recorded from isolated ampullae of Lorenzini of dogfishes (Scyliorhinus canicula). The ampullae were placed between two thermodes, each of which could be circulated separately with water at 12°, 18° and 24° C, thus allowing cooling and warming with various combinations of spatial temperature gradients. At constant temperature, there was a static discharge in the ampullary fibers. Cooling elicited a dynamic overshoot in frequency, followed by adaptation to a new steady state, whereas warming led to a transient inhibition. Within the limits of error the direction and slope of the spatial temperature gradient had no influence whatsoever on the static and dynamic responses of the ampullae, the only effective parameters being the temperature at the site of the receptor and the rate of temperature change with time.About 13% of the single fibers responded with bursts of impulses, interrupted by silent intervals, and 10% showed an inversed dynamic response, i.e. dynamic overshoot on warming and transient inhibition on cooling. It is possible that these patterns of activity are anomalous responses.This work was supported by the Deutsche Forschungsgemeinschaft.  相似文献   
19.
20.
Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies were carried out in random order on 13 healthy, exercise-trained thoroughbred horses, 7 days apart. An incremental exercise protocol leading to 120 s of galloping at 14 m s–1 on a 3.5% uphill incline was used. Galloping at this workload elicited maximal heart rate and induced pulmonary hemorrhage in all horses in both treatments. In the placebo study, arterial oxygen tension decreased to 76.1 (2) mmHg (P<0.0001) at 30 s of maximal exertion, but further significant changes did not occur as exercise duration increased to 120 s [arterial oxygen tension 72.4 (2) mmHg]. A significant arterial hypoxemia also developed in galloping horses in the acute hypervolemia study [arterial oxygen tension at 30 and 120 s was 76.7 (1.7) and 71.9 (1.6) mmHg, respectively], but significant differences between treatments could not be demonstrated. In both treatments, a similar desaturation of arterial hemoglobin was also observed at 30 s of maximal exercise, which intensified with increasing exercise duration as hyperthermia, acidosis and hypercapnia intensified. Thus, acute expansion of plasma volume did not benefit arterial oxygenation in maximally exercising thoroughbred horses.  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