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   544篇
  免费   32篇
  国内免费   1篇
耳鼻咽喉   17篇
儿科学   19篇
妇产科学   20篇
基础医学   55篇
口腔科学   54篇
临床医学   25篇
内科学   149篇
皮肤病学   3篇
神经病学   54篇
特种医学   3篇
外科学   53篇
综合类   1篇
预防医学   47篇
眼科学   9篇
药学   38篇
中国医学   7篇
肿瘤学   23篇
  2023年   4篇
  2022年   3篇
  2021年   16篇
  2020年   8篇
  2019年   7篇
  2018年   17篇
  2017年   13篇
  2016年   19篇
  2015年   13篇
  2014年   21篇
  2013年   31篇
  2012年   40篇
  2011年   57篇
  2010年   24篇
  2009年   14篇
  2008年   36篇
  2007年   49篇
  2006年   49篇
  2005年   45篇
  2004年   32篇
  2003年   27篇
  2002年   23篇
  2001年   9篇
  2000年   5篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1988年   1篇
  1985年   1篇
  1982年   1篇
  1914年   1篇
  1907年   1篇
排序方式: 共有577条查询结果,搜索用时 375 毫秒
31.
32.
Aim of this experimental study is to verify the protective effect of molsidomine on the renal function and structural modifications in the ischemia-reperfusion rat kidney. Sixty-eight male Sprague-Dawley rats, which were right nephrectomized and occluded left renal artery for 60 minutes were used. Group I (n = 10) Sham-Operated animals, which only underwent right nephrectomy. Group II (n = 20) Untreated ischemic rats, which underwent left renal ischemia by occlusion of the renal artery for 60 minutes before blood flow was restored. Group III (n = 18) Molsidomine treated ischemic rats, Group IV (n = 20) L-NAME (NG-nitro-L-arginine methyl ester) treated ischemic rats. Serum creatinine and blood urea nitrogen (BUN) were measured daily and biopsies were obtained from the remaining left kidneys. At seventh day, 55% and50% of the rats remained alive at the G-II and G-IV respectively. Molsidomine treated rats (G-III) were alive and healthy at day 7. The serum creatinine and BUN levels were significantly higher in G-II and G-IV when compared with the sham-operated group (G-I). G-III rats showed a rapid return to the normal serum creatinine and BUN values on postoperative days 1, 2, 3 and 4. The obtained values in G-III were significantly lower in comparison to the values of G-II and G-IV. The most severe damage (grade3 to 4) was determined in the kidneys of rats from GII or GIV. The degree of renal tubular damage in GIII was evaluated as grade 1 or 2 tubular damage according to Jablonkski's scale. Our findings suggested that the administration of molsidomine may vanquish the pernicious effects of warm ischemia on kidney structure and function. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
33.
34.
In this study, a new series of 1-[[alpha-(4-substitutedbenzoyloxy)-alpha-phenylacetyl or methylacetyl]amino]-5-(4-methoxyphenyl)-1,3,4-oxadiazoles were obtained by condensation of 2-[(alpha-chloro-alpha-phenylacetyl or alpha-bromopropionyl)amino]-5-(4-methoxyphenyl)1,3,4-oxadiazoles with sodium salts of 4-substituted benzoic acids. Structures of the compounds were assigned on the basis of spectral data (UV, IR, 1H NMR, El MS) and elemental analyses. The antibacterial activities of the novel compounds against Staphylococcus aureus ATCC 6538. Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri and Proteus mirabilis and antifungal activity against Candida albicans ATCC 10231 were tested using disk diffusion method. Compounds 4a, 4d and 4g were found to be active against S. aureus ATCC 6538 (MIC, 78, 39 and 78 microg ml(-1), respectively) and compound 4e against S. epidermidis ATCC 12228 (MIC, 156 microg ml(-1)).  相似文献   
35.
Nonstructural proteins of plum pox potyvirus were partially purified following a procedure described for the isolation of tobacco etch virus nuclear inclusion proteins. Plum pox virus proteins with electrophoretic mobilities corresponding to 49, 59 and 68 kDa reacted with antibodies against the 49 kDa and 54 kDa components of the nuclear inclusions and the 70 kDa component of the cylindrical inclusions of tobacco etch virus, respectively. Further purification by size exclusion high performance liquid chromatography or SDS-polyacrylamide gel electrophoresis, and amino terminal amino acid sequencing permitted the location in the plum pox virus polyprotein of the cleavage sites from which the 49 kDa (NIa-type, protease), 59 kDa (NIb-type, putative RNA replicase), and 68 kDa (CI-type) proteins originate. A 110 kDa protein which copurified with the plum pox virus inclusion proteins reacted with both anti-NIa and anti-NIb sera and had the same amino terminus as the plum pox virus 49 kDa protein, indicating that it is a non-processed 49-59 kDa polypeptide.  相似文献   
36.
37.
AIMS: The main purpose of this study was to evaluate the regional diastolic function in Chagas' disease using tissue Doppler imaging (TDI). METHODS AND RESULTS: Seventy-seven patients were evaluated and divided into three groups: group 0, control; group 1, chagasic patients with normal ECG; and group 2, chagasic patients with abnormal ECG. The following parameters were evaluated: E and A waves, E/A ratio, deceleration time and the isovolumic relaxation time by pulsed wave Doppler and analysis of early (e') and late (a') filling waves by means of TDI, in basal segment of the septal, anterior, inferior, posterior and lateral walls of the left ventricle. The only index of the transmitral flow that presented a significant difference between the chagasic patients and the controls was the deceleration time. As regards the TDI, a significant difference occurred between the various groups in relation to the e' wave, especially in the septal, inferior and posterior walls of the left ventricle. CONCLUSION: TDI proved itself a more sensitive technique for the study of the diastolic function in Chagas' disease than conventional Doppler echocardiography, bringing to light regional abnormalities and allowing differentiation between normal and chagasic individuals with or without cardiomyopathy. TDI could be potentially useful in clinical work and in the stratification of risk of these patients.  相似文献   
38.
GOALS OF WORK: This is a prospective and observational study comparing the efficacy of risk-assessment models in patients with neutropenic fever in a reference treatment center. The meaning of the complex infection was evaluated. MATERIALS AND METHODS: Patients were recruited throughout a 9-month period. Inclusion criteria were histologic diagnosis of malignancy, neutropenic febrile secondary to chemotherapy and/or radiotherapy (absolute neutrophil count of <500/microl and axillary temperature > or = 38 degrees C), and > or = 18 years of age. MAIN RESULTS: Fifty-three febrile neutropenic patients were included. Twenty one of them were classified as low risk by the Multinational Association of Supportive Care in Cancer (MASCC) risk-index score. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the MASCC risk-index scores were, respectively 87.9, 85.0, 90.6, 80.9, and 86.8%. None of the low-risk patients died, but four patients classified as low risk by the MASCC model developed serious medical complications during febrile neutropenic episodes. When we subtracted patients with complex infections from the group of patients with the MASCC risk-index score of > or = 21, we got 15 patients that were classified as low risk by a proposed adjustment by complex infection (PACI) model. None of them developed serious medical complications. The sensitivity, specificity, PPV, NPV, and the accuracy of this new model were, respectively, 100, 75.0, 86.8, 100, and 90.6%. CONCLUSION: The MASCC risk-index score had high sensitivity and specificity to predict the absence of complications, but the PACI model was better than MASCC for predicting the absence of complications in this febrile neutropenic patients.  相似文献   
39.
Nephrotoxicity is a major complication of acetaminophen (APAP), a widely used analgesic and antipyretic drug, and there is no specific treatment for APAP-induced renal damage. It has been reported that reactive oxygen metabolites or free radicals are important mediators of APAP toxicity. In this study, the protective role of melatonin (MLT) on APAP-induced nephrotoxicity was investigated in rats. For this purpose, nephrotoxicity was induced in male Wistar albino rats by intraperitoneal (i.p.) administration of a single dose of 1,000 mg/kg APAP. Some of these rats also received i.p. melatonin (10 mg/kg) 20 min after administration of APAP. The rats were sacrificed 24 h after administration of APAP. Urea and creatinine levels were measured in the blood, and levels of malondialdehyde (MDA) and glutathione (GSH), and glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity were determined in renal tissue. Serum urea and creatinine levels increased significantly as a result of APAP nephrotoxicity. A significant increase in MDA and decreases in GSH level and GSH-Px, CAT, and SOD activity indicated that APAP-induced renal damage was mediated through oxidative stress. Significant beneficial changes were noted in serum and tissue oxidative stress indicators in rats treated with MLT. These biochemical observations were supplemented by histopathological examination of kidney sections, which revealed that MLT also reduced the severity of APAP-induced histological alterations in the kidney. These results indicate that administration of APAP causes oxidative stress to renal tissue and that MLT protects against the oxidative damage associated with APAP.  相似文献   
40.
The antiphospholipid syndrome (APS) is characterized by obstetric and thrombotic complications in the presence of antiphospholipid antibodies. It can happen in an isolated way or in association with diffuse connective tissue diseases, mainly systemic lupus erythematosus. The association of APS with Takayasu arteritis (TA) is rarely described in the literature. We described a case of primary APS in a female patient who developed obstruction in large-size arteries, in spite of the use of oral anticoagulant, and increase of erythrocyte sedimentation rate, suggesting TA. The favorable response to prednisone treatment and later to infliximab reinforced the diagnosis of TA. The present report illustrates the existence of APS associated to TA, whose recognition is very important once the therapeutic strategy is radically different.  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