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   18871篇
  免费   900篇
  国内免费   87篇
耳鼻咽喉   136篇
儿科学   265篇
妇产科学   340篇
基础医学   2533篇
口腔科学   486篇
临床医学   1201篇
内科学   4730篇
皮肤病学   275篇
神经病学   1611篇
特种医学   760篇
外科学   3032篇
综合类   88篇
一般理论   1篇
预防医学   515篇
眼科学   531篇
药学   1458篇
中国医学   65篇
肿瘤学   1831篇
  2022年   160篇
  2021年   263篇
  2020年   215篇
  2019年   228篇
  2018年   287篇
  2017年   227篇
  2016年   306篇
  2015年   300篇
  2014年   413篇
  2013年   517篇
  2012年   823篇
  2011年   863篇
  2010年   486篇
  2009年   392篇
  2008年   767篇
  2007年   798篇
  2006年   727篇
  2005年   773篇
  2004年   852篇
  2003年   774篇
  2002年   794篇
  2001年   800篇
  2000年   828篇
  1999年   748篇
  1998年   253篇
  1997年   191篇
  1996年   163篇
  1995年   150篇
  1994年   149篇
  1993年   127篇
  1992年   536篇
  1991年   456篇
  1990年   464篇
  1989年   468篇
  1988年   412篇
  1987年   351篇
  1986年   349篇
  1985年   349篇
  1984年   242篇
  1983年   180篇
  1982年   83篇
  1979年   165篇
  1978年   119篇
  1977年   115篇
  1974年   88篇
  1972年   89篇
  1971年   95篇
  1970年   83篇
  1968年   94篇
  1967年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Limited vertical skin incision for median sternotomy.   总被引:4,自引:0,他引:4  
The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.  相似文献   
72.
Inhibitory effects of the calcium channel blocker nisoldipine on angiotensin II-induced antidiuresis were investigated in anesthetized dogs, and the findings were compared with those of saralasin. Intrarenal arterial infusion of 10 ng/kg/min angiotensin II resulted in marked decreases in renal blood flow (RBF) and urine formation, with a relatively moderate decrease in glomerular filtration rate. There were marked reductions in the fractional excretion of lithium, which is used as an index of the fractional proximal excretion of sodium, and the fractional distal excretion of sodium. Nisoldipine (50 ng/kg/min) administered intrarenally produced a partial inhibition on the decreased response of RBF to angiotensin II. The peptide-induced decreases in urine flow, urinary excretion of electrolytes and fractional excretion of electrolytes were abolished by nisoldipine. In contrast, when saralasin was administered intrarenally at 10 ng/kg/min, a dose which could partially inhibit the angiotensin II-induced decrease in RBF to the same extent as seen with nisoldipine, the antagonist attenuated, but did not abolish, the antidiuretic action of angiotensin II. Significant decreases in urine formation by angiotensin II were observed, even in the presence of saralasin. These results suggest that nisoldipine, unlike saralasin, preferentially interferes with the stimulatory effect of angiotensin II, as related to the renal tubular reabsorption of sodium and water.  相似文献   
73.
Mutations in the dysferlin gene (DYSF) on chromosome 2p13 cause distinct phenotypes of muscular dystrophy: limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy, which are known by the term 'dysferlinopathy'. We performed mutation analyses of DYSF in 14 Italian patients from 10 unrelated families with a deficiency of dysferlin protein below 20% of the value in normal controls by immunoblotting analysis. We identified 11 different mutations, including eight missense and three deletion mutations. Nine of them were novel mutations. We also identified a unique 6-bp insertion polymorphism within the coding region of DYSF in 15% of Italian population, which was not observed in East Asian populations. The correlation between clinical phenotype and the gene mutations was unclear, which suggested the role of additional genetic and epigenetic factors in modifying clinical symptoms.  相似文献   
74.
75.
76.
Both goldthioglucose (GTG)-treated and the genetically obese (C57BL/6J ob/ob) mice were fed semisynthetic diets containing either soy protein isolate (SPI) or casein as a protein source, or laboratory chow. In GTG-induced obese mice, the plasma cholesterol level correlated positively with their body weight. The level was highest in mice fed high-fat diet, and lowest in ones fed laboratory chow. No difference was observed between SPI and casein groups whether the diet was low-fat or high-fat. Thus, in the GTG-treated mice, SPI did not have a hypocholesterolemic effect while dietary fat had a hypercholesterolemic effect, and laboratory chow contained some component(s) which can lower the plasma cholesterol level. Both neutral and acidic steroid contents in feces of the SPI group were not different from those of the casein group, and both groups of mice excreted a smaller amount of steroids than mice fed laboratory chow. Results of essentially the same tendency were obtained with normal mice regarding the effects of SPI and casein, although the degree of hypercholesterolemia was lower in high-fat-fed normal mice than in similarly fed GTG-treated mice. These results strengthened the inverse correlation between the amount of fecal steroids and the plasma cholesterol level upon feeding various proteins, indicating that the former is one of the important factors that determine the latter. The ob/ob mice showed a marked hypercholesterolemia irrespective of the kind of diet. The amount of fecal steroids was highest in the laboratory chow group and lowest in the casein group. This indicates that some factor(s) other than fecal steroid excretion is dominantly responsible for their hypercholesterolemia.  相似文献   
77.
Twenty-two children were monitored by the auditory brainstem response (ABR) during the open chest and/or open heart surgery for cardiac anomalies under the extracorporeal circulation (ECC) with moderate to deep hypothermia. These patients were divided into two groups, namely, the ECC only group (group A: 9 cases) and the total circulatory arrest (TCA) group (group B: 13 cases). The mean age of group A was 36 months and group B was 6.1 months. In group A, moderate hypothermia was conducted with the rectal temperature ranging from 25 degrees C to 30 degrees C, and in group B profound hypothermia was conducted lowering the temperature to 18 degrees C. The ABR recorded at the following points, namely; before inducing anesthesia, before lowering the body temperatures, during the cooling process, at the time of TCA, and during the rewarming process. Accompanying the decrease in body temperature the peak latency of waves I, III and V were markedly prolonged. When the rectal temperature fell to 23 degrees C, the peak latency of each wave was prolonged to about 150% of their precooling values at 36 degrees C. When it fell to 22 degrees C, the ABR disappeared entirely in 16 of 22 cases, and in remaining 6 cases, only I wave was detected. During rewarming, in both the A and B groups, at 24 degrees C, the wave of ABR started to reappear beginning with I waves, and on reaching 26 degrees C, I, III and V waves from became detectable. The peak latency of all waves at rectal temperature of 33 degrees C recovered to almost the same values as these at 36 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
78.
PAF-likely activity, detected as aggregation of washed platelets, was found in the exudate of rats with pleurisy induced by phorbol myristate acetate (PMA, 1 nmol). At 30 min after the injection of PMA, 400-500 pg of PAF was detected in the pleural exudate. An extract of the exudate was made and analysed by HPLC and by rabbit platelet aggregation. The activity was characterized as that of PAF as a result of the inhibition seen with the PAF-antagonist CV-3988 and the loss of activity by treatment with phospholipase A2. Indirect evidence was previously reported in that CV-3988 suppressed the pleural fluid accumulation in the pleurisy induced by PMA. Taken together these facts it indicates that PAF could be an important mediator of acute inflammation, especially of the plasma exudation resulting from an increase in vascular permeability. Evidence that pleural cells produce PAF was also examined in an in vitro experiment. PAF was found in the supernatant and cellular fractions of the incubation mixture of the pleural cells from normal rats when stimulated by PMA (1 microM) or A23187 (5 microM), and the results indicate that the pleural cells produce PAF and release a portion of it.  相似文献   
79.
80.
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