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   24506篇
  免费   1960篇
  国内免费   1369篇
耳鼻咽喉   3篇
儿科学   353篇
妇产科学   47篇
基础医学   1696篇
口腔科学   21篇
临床医学   2536篇
内科学   9217篇
皮肤病学   39篇
神经病学   182篇
特种医学   1242篇
外国民族医学   10篇
外科学   2398篇
综合类   4667篇
现状与发展   6篇
预防医学   816篇
眼科学   10篇
药学   2263篇
  13篇
中国医学   1287篇
肿瘤学   1029篇
  2024年   47篇
  2023年   318篇
  2022年   510篇
  2021年   724篇
  2020年   716篇
  2019年   626篇
  2018年   633篇
  2017年   776篇
  2016年   971篇
  2015年   978篇
  2014年   1524篇
  2013年   1581篇
  2012年   1465篇
  2011年   1609篇
  2010年   1292篇
  2009年   1361篇
  2008年   1292篇
  2007年   1312篇
  2006年   1286篇
  2005年   1101篇
  2004年   818篇
  2003年   815篇
  2002年   725篇
  2001年   648篇
  2000年   560篇
  1999年   422篇
  1998年   425篇
  1997年   394篇
  1996年   386篇
  1995年   309篇
  1994年   303篇
  1993年   250篇
  1992年   236篇
  1991年   212篇
  1990年   158篇
  1989年   145篇
  1988年   133篇
  1987年   103篇
  1986年   90篇
  1985年   100篇
  1984年   75篇
  1983年   43篇
  1982年   59篇
  1981年   54篇
  1980年   50篇
  1979年   47篇
  1978年   30篇
  1977年   39篇
  1976年   19篇
  1975年   21篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
The haemodynamic effects of nitrovasodilators and their mechanisms of action on portal hypertension remain unclear. The splanchnic and systemic haemodynamic response to the infusion of isosorbide dinitrate (100 μg/kg per min), a nitrovasodilator, was investigated in cirrhotic rats. The role of the conscious state in the haemodynamic response to isosorbide dinitrate was examined using rats that were anaesthetized with pentobarbitone. The role of sympathetic tone in the haemodynamic response to isosorbide dinitrate was examined using rats pretreated with the ganglion blocker hexamethonium. Isosorbide dinitrate had no haemodynamic effects in conscious, unblocked normal and cirrhotic rats. Isosorbide dinitrate had no haemodynamic effects in normal and cirrhotic rats treated with hexamethonium. In normal anaesthetized rats, isosorbide dinitrate significantly decreased systemic vascular resistance (414±25 vs 290±26 dyn.s/cm5 per 100 g). In cirrhotic anaesthetized rats, isosorbide dinitrate significantly decreased mean arterial pressure (98±6 vs 79±7 mmHg), systemic vascular resistance (318±30 vs 207±10 dyn.s/cm5 per 100 g), portal pressure (14.0±1.0 vs 11.3±0.9 mmHg) and portal territory vascular resistance (1362±163 vs 1031±182 dyn.s/cm5 per 100 g). In conclusion, this study shows that the portal hypotensive effects of isosorbide dinitrate depend upon the alterations of vascular tone by pentobarbitone.  相似文献   
82.
Summary Four hundred and seventy villagers of Ndombo, a village with recently established intensive transmission of Schistosoma mansoni in the Senegal River Basin, were enrolled in a study with the intention to assess hepatosplenic morbidity. All patients were examined parasitologically and by ultrasound. Hepatic fibrosis serum markers were determined in 153 adult patients (aminoterminal propeptide of procollagen type III, hyaluronan and laminin). By ultrasound, about 60% of the patients showed early stages of hepatic involvement, 3% of the patients unequivocally showed severe hepatosplenic pathology (grade 3 according to the Managil classification), whereas in another study performed in the same village 3 years earlier, no patients with severe hepatosplenic pathology had been found. No correlation between the aminoterminal propeptide of procollagen type III, hyaluronan or laminin and the ultrasound findings could be established. These hepatic fibrosis serum markers do not seem to be a sensitive method to detect early hepatic fibrosis in schistosomiasis.  相似文献   
83.
A case of small fibrolamellar hepatocellular carcinoma (HCC) coexistent with a HCC of common type is herein reported. A 56-year-old man was diagnosed as having multi-nodular type HCC with liver cirrhosis. The serum alpha-fetoprotein (AFP) level was slightly increased. The patient underwent a partial caudate lobectomy and lateral segmentectomy. Histologically, both resected tumors were small HCCs measuring less than 2 cm in diameter. One was a fibrolamellar type located in the caudate lobe, while the other was the common type in the lateral segment of the liver. Positive immunohistochemical staining for AFP was observed in the tumor cells of the HCC of common type but was not observed in the fibrolamellar HCC. We also reviewed previously reported cases of fibrolamellar HCC in Japan, and discussed the clinicopathologic implications of this disease.  相似文献   
84.
The results of treating 12 consecutive patients with unresectable colorectal hepatic metastases with a hepatic arterial infusion of high-dose Adriamycin, 100–120 mg/m2, using hepatic venous isolation (HVI) and charcoal hemoperfusion (CHP) are reported herein. Adriamycin was administered over 5–15 min under extracorporeal drug elimination by HVI-CHP. HVI was percutaneously accomplished by either the double-balloon technique using a Fogarty occlusion catheter (8/22F) or a balloon-tipped catheter (16F). During the infusion, isolated hepatic venous blood was filtered by CHP and pumped into the left axillary vein. There were no lethal complications, and good hemodynamic tolerance to HVI-CHP was confirmed. Tumor liquefaction accompanied by a sharp decrease in serum carcinoembryonic antigen levels by more than 50% of pretreatment levels was observed in 6 of the 12 patients 1 month after treatment. Apart from chemical hepatitis, which developed in 11 (92%) of the patients, the Adriamycin toxicities were well controlled following the development of nausea and vomiting in 2 patients (17%), leukopenia <2,000/mm3 in 3 (25%), and gastric ulcer in 1 (8%). These results indicate that this method is a safe and useful procedure for otherwise hazardous high-dose intraarterial chemotherapy in patients with unresectable hepatic tumors.  相似文献   
85.
Hepatic angiomyolipoma is a rare tumor composed of spindle-shaped and epithelioid smooth muscle cells, adipose tissue, and proliferating blood vessels. We report the first documented case of this tumor developing in a patient with ulcerative colitis. A solitary tumor (7.5×7.5×7cm) was detected in the left lateral segment of the liver and a left hepatic lobectomy was performed. The diagnosis of angiomyolipoma was confirmed by a pathological examination. We also review the literature on previously reported cases of hepatic angiomyolipoma.  相似文献   
86.
87.
采用从新生牛肝脏提取的肝细胞再生刺激因子(cHSS)治疗慢性病毒性肝炎82例,总有效率89.0%,与对照组(76.5%)比较有显著性差异(P<0.05)。经治疗后cHSS组病人乏力、纳差、腹胀等症状的改善明显优于对照组,ALT恢复与黄疸消退均较对照组迅速(P<0.01)。治疗过程中未发现任何副作用。提示cHSS对慢性肝炎有较好的疗效,能促进肝功能恢复。  相似文献   
88.
Abstract Somatostatin has been used to effectively control acute variceal haemorrhage, with conjectured mechanisms on portal hypertension. We, therefore, evaluated the effects of somatostatin on hepatic and systemic haemodynamics in 15 patients with hepatitis B-related cirrhosis and portal hypertension. All patients received an intravenous, continuous infusion of somatostatin 250 μg/h, following a bolus injection of 250 μg. In systemic haemodynamics, the mean arterial pressure (MAP) increased ( P < 0.05), associated with a reflex bradycardia within 3 min following bolus injections, compared with basal values. The right atrial pressure, pulmonary capillary wedge pressure, inferior vena cava pressure, cardiac index, and systemic vascular resistance remained unaffected after drug infusion. In hepatic haemodynamics, the wedge hepatic vein pressure remained unchanged after drug administration. However, there was an increase in free hepatic vein pressure (FHVP; P < 0.05), and a trend toward a decrease in the hepatic vein pressure gradient (HVPG; P = 0.063), within 3 min after bolus injection. Furthermore, the hepatic blood flow decreased significantly at 10 and 30 min after somatostatin infusion ( P < 0.05). The effective sinusoidal perfusion assessed by indocyanine green infusion also decreased progressively at 10 min ( P = 0.057) and 30 min ( P < 0.05). We concluded that somatostatin, at the dose used in this study, caused a transient and bolus-related vasoconstrictive effect, resulting in increases in MAP and FHVP, a decrease in heart rate, and a trend toward lower HVPG. In addition, somatostatin reduced the hepatic blood flow and effective sinusoidal perfusion which may be hazardous to cirrhotic patients during variceal haemorrhage.  相似文献   
89.
对29例亚急性重症肝炎及13例次淤胆性肝炎肝穿刺标本的光、电镜检查,测算了18例亚急性重症肝炎,9例淤胆性肝炎肝细胞内淤胆的容积百分比、胆汁凝固性坏死的容积百分比与临床资料进行统计学处理,指出这两类肝炎都有肝细胞内淤胆和胆汁凝固性坏死,但淤胆性肝炎肝小叶结构完整,胆汁流出道不破坏,亚急性重症肝炎肝小叶破坏。认为除肝细胞大量坏死外,胆汁流出道破坏是影响预后的另一个重要因素。本文详细描述了胆计凝固性坏死的超微结构改变。  相似文献   
90.
Summary The serum concentrations of 1-acid glycoprotein (AAG), albumin (HSA) and non-esterified fatty acids, and the serum binding of tertatolol were measured in four groups of individuals: healthy control subjects (n=24), and patients with inflammation (n=28), and hepatic (n=20) and renal (n=27) insufficiency.Serum binding of tertatolol was increased in patients with inflammation (94.6%), decreased in patients with hepatic insufficiency (88.8%) and it was unchanged in patients with renal insufficiency (92.8%) as compared to controls (92.7%).Multivariate analysis indicated that the changes were mainly related to concomitant changes in AAG concentration, which could account for 57% of intersubject variability in the bound/free ratio, and to a lesser extent in HSA, which accounted for only 4% of the variability in the binding.The data show that the free fraction of the basic drug tertatolol in serum is affected by pathological conditions that cause changes in AAG concentration.  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