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   1277562篇
  免费   92825篇
  国内免费   1992篇
耳鼻咽喉   18190篇
儿科学   42337篇
妇产科学   37849篇
基础医学   187071篇
口腔科学   35393篇
临床医学   108243篇
内科学   251744篇
皮肤病学   26517篇
神经病学   99234篇
特种医学   50000篇
外国民族医学   366篇
外科学   197705篇
综合类   26548篇
现状与发展   1篇
一般理论   300篇
预防医学   92642篇
眼科学   29069篇
药学   97814篇
  1篇
中国医学   2498篇
肿瘤学   68857篇
  2018年   11828篇
  2015年   11655篇
  2014年   16030篇
  2013年   24404篇
  2012年   33611篇
  2011年   36017篇
  2010年   21262篇
  2009年   20060篇
  2008年   35021篇
  2007年   37989篇
  2006年   38547篇
  2005年   37829篇
  2004年   36416篇
  2003年   35405篇
  2002年   34951篇
  2001年   58116篇
  2000年   59605篇
  1999年   50700篇
  1998年   14238篇
  1997年   12812篇
  1996年   13077篇
  1995年   12350篇
  1994年   11768篇
  1993年   10864篇
  1992年   41010篇
  1991年   40374篇
  1990年   39895篇
  1989年   38714篇
  1988年   36115篇
  1987年   35354篇
  1986年   33730篇
  1985年   32142篇
  1984年   23926篇
  1983年   20819篇
  1982年   12384篇
  1981年   10935篇
  1980年   10207篇
  1979年   22647篇
  1978年   15887篇
  1977年   13737篇
  1976年   12978篇
  1975年   14204篇
  1974年   16685篇
  1973年   16087篇
  1972年   15321篇
  1971年   14234篇
  1970年   13219篇
  1969年   12735篇
  1968年   11985篇
  1967年   10486篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans.  相似文献   
82.
Pulmonary valve insertion during reoperation for tetralogy of Fallot   总被引:1,自引:0,他引:1  
Our experience with pulmonary valve insertion during reoperation for residual lesions after initial open repair of tetralogy of Fallot in 15 patients is reported. Preoperatively, 14 patients were in moderate to severe congestive heart failure, and all 15 had decreased right ventricular (RV) function at cardiac catheterization. All 15 patients had pulmonary insufficiency but not as an isolated finding. The most common residual lesions encountered were ventricular septal defect in 9, tricuspid insufficiency in 11, and peripheral pulmonary arterial stenosis in 6. Tissue valves were inserted in all patients. Mean peak RV-left ventricular pressure ratio measured in the operating room decreased from 0.61 +/- 0.10 (+/- the standard deviation) to 0.47 +/- 0.17 (p less than 0.05). There were no operative deaths. At follow-up (mean, 33 months), all but 1 patient were in New York Heart Association Class I or II. Pulmonary valve insertion should be considered during reoperation for tetralogy of Fallot when pulmonary insufficiency and RV failure are present.  相似文献   
83.
84.
Median cervical cysts are congenital anomalies arising from remaining thyroglossal duct epithelium. A major problem in the surgical treatment of these cysts is the high frequency of recurrence. Embryonic considerations indicate an important causal role for the hyoid bone in these recurrences. We studied the relationship between operative techniques and the number of recurrences in 36 patients treated in our hospital. Fourteen patients sent from other hospitals had a recurrent fistula; in thirteen cases the hyoid bone was still in place. All patients who had the central part of the hyoid bone excised were cured. In 14 patients without adequate excisions of the hyoid bone we found four recurrences. To prevent recurrence a total excision of thyroglossal duct epithelium is necessary.  相似文献   
85.
Eighty-eight patients with blunt renal trauma were examined sonographically. Rupture of the kidney was diagnosed in 41 patients and contusion of the kidney in 45. The correlation between operative findings, sonography and urography showed positive sonographic findings to be correct in all patients with rupture of the kidney. In 4 patients with normal sonograms, the diagnosis of a contusion was based on the urographic results. Three patients underwent angiography. An intimal lesion was seen in 2 and a tear of the renal artery in 1. The results of our investigation suggest that sonography should be applied in the first place in the evaluation of blunt renal trauma. It is the investigation of choice during follow-up after surgical as well as conservative therapy.  相似文献   
86.
87.
Multiple trauma is often associated with blunt thoracic injuries. Especially lung contusion can result in respiratory insufficiency and therefore a higher mortality rate. In our prospective study comparing 8 multiple trauma patients with and without associated lung contusion, we found that respiratory function was already significantly disturbed (decrease of paO2/FiO2 and increase of AaDO2, a rise in extravascular lung water (EVLW) both early after trauma and also with a second peak following the 4th day. This group (LK) developed significantly more cases of respiratory distress (ARDS). The disturbance of respiratory function seen initially was interpreted as a consequence of the direct mechanical impact, leading to the formation of interstitial fluid and hematoma. The frequent development of ARDS in the LK-group probably results from a pronounced activation of cellular and humoral mechanisms and therefore an enforced injury of the pulmonary capillary bed. A significant increase of pulmonary infections or the development of sepsis was not seen in the LK-group and is probably not responsible for the higher ARDS-rate in this group.  相似文献   
88.
89.
90.
Concanavalin A-induced lymphocyte proliferation was studied in 25 patients with alcoholic hepatitis or compensated alcoholic cirrhosis. Nine alcoholics without evidence of liver disease were also evaluated. A nonlinear correlation equation, which was natural logarithmic, was applied to individual dose-response proliferation curves and permitted comparisons between patient groups and controls. The proliferative response in all patient groups was significantly lower when compared to healthy controls and was independent of the presence or absence of liver disease. This suggests that some changes in immune function observed in alcoholics may be linked to the direct effects of alcohol on the immune system rather than to the associated liver disease.  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