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   2787篇
  免费   124篇
  国内免费   30篇
耳鼻咽喉   7篇
儿科学   115篇
妇产科学   59篇
基础医学   521篇
口腔科学   77篇
临床医学   288篇
内科学   666篇
皮肤病学   116篇
神经病学   133篇
特种医学   269篇
外国民族医学   1篇
外科学   268篇
综合类   54篇
一般理论   1篇
预防医学   100篇
眼科学   35篇
药学   148篇
中国医学   1篇
肿瘤学   82篇
  2018年   30篇
  2015年   37篇
  2014年   38篇
  2013年   95篇
  2012年   56篇
  2011年   46篇
  2010年   58篇
  2009年   45篇
  2008年   39篇
  2007年   74篇
  2006年   85篇
  2005年   54篇
  2004年   47篇
  2003年   46篇
  2002年   38篇
  2001年   50篇
  2000年   39篇
  1999年   45篇
  1998年   84篇
  1997年   96篇
  1996年   105篇
  1995年   70篇
  1994年   75篇
  1993年   77篇
  1992年   47篇
  1991年   48篇
  1990年   54篇
  1989年   77篇
  1988年   69篇
  1987年   58篇
  1986年   67篇
  1985年   42篇
  1984年   65篇
  1983年   35篇
  1982年   33篇
  1981年   41篇
  1980年   51篇
  1979年   30篇
  1978年   34篇
  1977年   42篇
  1976年   41篇
  1975年   42篇
  1971年   30篇
  1970年   30篇
  1965年   50篇
  1964年   50篇
  1963年   47篇
  1962年   41篇
  1961年   40篇
  1960年   66篇
排序方式: 共有2941条查询结果,搜索用时 15 毫秒
1.
2.
An electromyographic study of the masseter and anterior part of the temporalis muscles was performed on ten patients presenting temporomandibular joint dysfunction symptoms. The EMG silent periods (SP) produced in the open-close-clench cycle and jaw-jerk reflex were compared for duration before and after treatment with an occlusal bite splint. Following use of the splint, there was a shortening of SP indicating the possible use of the duration of SP as a diagnostic measurement, and also as an indication of treatment effectiveness.  相似文献   
3.
The effects of varying clinically relevant patterns of anaesthetic-vasoconstrictor combinations used for peri-radicular surgery on plasma concentrations of catecholamines and haemodynamic responses was studied in the canine model. Five mongrel dogs were anaesthetized with sodium pentobarbital. A femoral canula was inserted to measure central blood pressure and an ECG was used to monitor heart rate and any associated arrhythmias. Femoral venous blood samples were drawn before initial injection and at 3 and 10 min after injections. Plasma catecholamine concentrations were determined using high pressure liquid chromatography (HPLC). Injection protocols used three time periods, 30, 60 and 90s, with solutions containing 1:100000 and 1:50000 adrenaline. No significant changes in heart rates or presence of arrythymias were noted over the experimental protocol. Catecholamine levels in pico moles mL-1 were within the normal range at the 3-min sample level. At the 10-min sample time there was a more erratic range of concentrations, with most samples within the normal range. This may have been due to endogenous release of catecholamines in specific animals. The data identified trends in both the haemodynamic parameters and plasma catecholamine levels that can legitimately support the careful use of higher levels of a vasoconstrictor when patient profiles and surgical needs dictate.  相似文献   
4.
The German-Swiss modernist painter Paul Klee (1879–1940) suffered in the final years of his life from a severe illness, diagnosed in 1936 as scleroderma, later renamed SSc. New classification criteria for this disease issued in 2013 now allow for a diagnosis to be confirmed. Important for this process, however, is the question of whether or not Klee’s hands were affected by his illness. The morphology of the artist’s hands and evidence of dysgraphic changes in his handwriting are reviewed as indications of his manual pathology. Despite his illness, Klee triumphed over his infirmity, simplifying his painting and drawing styles and substantially increasing his artistic output from 1936 until his death in 1940.  相似文献   
5.

Background

The purpose of this study was to determine the changes in vertebral column height (VCH) of males and females, at every one-half mile, for a total walking distance of 3 miles.

Methods

Twenty males and twenty females between the ages of 21 and 40 years walked 3 miles on a treadmill maintaining a walking speed that the subject rated between 12 and 14 on Borg''s rate of perceived exertion scale. Blood pressure, heart rate, and VCH measurements were taken initially and at each half-mile interval throughout the three-mile walk. Vertebral column height (VCH) was measured from the spinous process of C7 to S2 using a standard tape measure.

Results

Significant differences existed in vertebral column height according to sex (F = 16.18; p < .05) and significant differences in vertebral column height at the different distances (F = 65.02: p < .0001). Significant changes occurred in the VCH between half-mile intervals only between 0.5 miles and 1.0 mile and between 1.0 mile and 1.5 miles during the walk. As found with a regression analysis, curvilinear relationship exists between the distance walked and VCH; with VCH decreasing throughout the distance of the walk.

Conclusions

Vertebral column height decreased in a curvilinear relationship throughout the distance of walking 3 miles in both males and females.  相似文献   
6.
To determine the factors that influenced doctors' prioritization and decisions on safe waiting time for coronary artery bypass surgery, 50 'paper patients', based on a random sample of cases who actually had surgery, were assessed by 33 clinicians. We used linear regression models to reflect the impact of clinical and non-clinical 'cues' on safe waiting time and priority decisions. The benefits of surgery tended to be over-estimated. For example, the average perceived gain in life expectancy for patients with left main-stem disease was 6.74 years. However, models incorporating only the perceptions of benefit as independent variables (i.e. the anticipated symptom reduction, MI risk reduction and life expectancy extension), had only modest explanatory power (mean R2 was 0.55 for safe waiting time, and 0.56 for priority decisions). Models which incorporated perceptions of benefit and the cases' clinical and non-clinical characteristics had generally much higher explanatory power (mean R2, 0.83 and 0.86, respectively). Lifestyle and demographic variables had much less impact on the doctors' judgements than the major clinical cues of angina severity and left main-stem stenosis. Demographic and lifestyle cues had different impacts on safe waiting time and priority for about 25% of doctors.   相似文献   
7.
8.
9.
There is abundant evidence of immune modulation induced by exposure to blood transfusions. Some studies have demonstrated a detrimental effect of transfusion on the recurrence of malignant disease and survival. We retrospectively studied the impact of blood transfusion exposure on 229 patients with breast cancer who were seen from July 1973 to September 1980, had at least 5 years' follow-up and had been randomized by therapy at the time of diagnosis. The patients were divided into four groups according to transfusion history: Group 1 (111 patients), no transfusion; Group 2 (34 patients), first transfusion after mastectomy; Group 3 (41 patients), first transfusion at mastectomy; and Group 4 (43 patients), first transfusion before mastectomy. All transfused patients received red cells or whole blood or both. At the time of analysis, 124 (54%) of the patients had died. Only Group 2 was statistically associated with decreased survival; recurrence of disease was 85 percent in this group, compared with 53 percent to 61 percent in the other three groups (p = 0.006, log-rank test). In general, Group 2 patients received transfusions because of recurrent disease. We conclude that transfusions before or at mastectomy are not associated with increased recurrence or reduced survival in patients with breast cancer.  相似文献   
10.
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