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   7632篇
  免费   335篇
  国内免费   33篇
耳鼻咽喉   163篇
儿科学   131篇
妇产科学   189篇
基础医学   941篇
口腔科学   169篇
临床医学   531篇
内科学   1905篇
皮肤病学   171篇
神经病学   556篇
特种医学   157篇
外科学   1093篇
综合类   81篇
预防医学   678篇
眼科学   183篇
药学   408篇
中国医学   32篇
肿瘤学   612篇
  2023年   46篇
  2022年   96篇
  2021年   230篇
  2020年   121篇
  2019年   214篇
  2018年   232篇
  2017年   142篇
  2016年   149篇
  2015年   172篇
  2014年   263篇
  2013年   355篇
  2012年   590篇
  2011年   629篇
  2010年   359篇
  2009年   363篇
  2008年   542篇
  2007年   533篇
  2006年   464篇
  2005年   497篇
  2004年   443篇
  2003年   377篇
  2002年   437篇
  2001年   54篇
  2000年   60篇
  1999年   79篇
  1998年   54篇
  1997年   57篇
  1996年   44篇
  1995年   32篇
  1994年   37篇
  1993年   39篇
  1992年   25篇
  1991年   21篇
  1990年   14篇
  1989年   19篇
  1988年   20篇
  1987年   10篇
  1986年   15篇
  1985年   10篇
  1984年   16篇
  1983年   11篇
  1982年   19篇
  1980年   13篇
  1979年   5篇
  1978年   10篇
  1976年   6篇
  1975年   5篇
  1974年   11篇
  1973年   5篇
  1971年   6篇
排序方式: 共有8000条查询结果,搜索用时 0 毫秒
131.
Background: The activity of N-methyl-D-aspartate (NMDA) glutamate receptor, which responds to the levels of polyamines, modifies the neurotoxicity caused by ethanol. We aimed to investigate if the functionality of the spermidine/spermine N1-acetyltransferase (SSAT1) gene could be associated with a differential risk for alcoholism. Methods: We studied a sample of 586 subjects: 104 alcohol-dependent patients, 273 patients with psychiatric disorders but without substance dependence, and 209 healthy controls. After gender stratification, the allele frequency distribution of the SSAT1 gene was compared between these three groups. Results: In females, the TC genotype was significantly more frequent in alcohol-dependent patients than in non-alcohol-dependent psychiatric controls (χ2?=?7.509 df?=?2, p?=?0.023). A trend was found when alcohol-dependent females were compared with the healthy control group (χ2?=?4.897 df?=?2, p?=?0.086). No statistical differences were found among the males. Discussion and conclusion: Gender differences in the regulation of SSAT1 gene expression may possibly be due to gender-specific effects of stress, ethanol toxicity, and/or polyamines levels. Further studies are needed to confirm our findings.  相似文献   
132.
133.
134.
135.
The risk of stroke in patients hospitalized with an acute coronary syndrome (ACS) ranges from <1% to ≥2.5%. The aim of this study was to develop a simple predictive tool for bedside risk estimation of in-hospital ischemic stroke in patients with ACS to help guide clinicians in the acute management of these high-risk patients. Data were obtained from 63,118 patients enrolled from April 1999 to December 2007 in the Global Registry of Acute Coronary Events (GRACE), a multinational registry involving 126 hospitals in 14 countries. A regression model was developed to predict the occurrence of in-hospital ischemic stroke in patients hospitalized with an ACS. The main study outcome was the development of ischemic stroke during the index hospitalization for an ACS. Eight risk factors for stroke were identified: older age, atrial fibrillation on index electrocardiogram, positive initial cardiac biomarkers, presenting systolic blood pressure ≥160 mm Hg, ST-segment change on index electrocardiogram, no history of smoking, higher Killip class, and lower body weight (c-statistic 0.7). The addition of coronary artery bypass graft surgery and percutaneous coronary intervention into the model increased the prediction of stroke risk. In conclusion, the GRACE stroke risk score is a simple tool for predicting in-hospital ischemic stroke risk in patients admitted for the entire spectrum of ACS, which is widely applicable to patients in various hospital settings and will assist in the management of high-risk patients with ACS.  相似文献   
136.
Surprisingly, little data are available for the use of disease-modifying antirheumatic drugs in ankylosing spondylitis. Sulfasalazine has been the best studied. Efficacy data for individual agents (including pamidronate) and combinations of agents are detailed in this review. Intriguingly, these agents continue to be used with some frequency, even in the absence of efficacy data. To answer these questions, additional systematic studies of these agents in ankylosing spondylitis are needed and will likely need to be done by interested collaborative groups such as SPARTAN.  相似文献   
137.
Here we compare the management and survival outcomes of chronic myeloid leukemia (CML) patients who had early or late imatinib mesylate (IM) therapy. The cytogenetic and molecular responses of 189 CML patients were analyzed. Of this group, 121 patients were classified as the early chronic phase (ECP) group and started IM within 12 months of diagnosis. The other 68 patients were classified as the late chronic phase (LCP) group who had been treated with interferon (IFN)-alpha-2 and crossed over to IM more than 12 months after diagnosis. The overall rates of complete cytogenetic response (CCyR) and major molecular response (MMR) at last follow-up were 83.6 and 78.1% in the ECP and LCP groups, respectively. The CCyR rates were 89.3 (for ECP patients) versus 73.5% (for LCP patients; p < 0.0001). At last follow-up, 82.4% ECP and 64.2% LCP patients had achieved an MMR (p < 0.0001). No significant differences were noted between the two groups with regard to survival outcomes. Our experience reveals that IM is an effective rescue therapy in most CML LCP patients who are intolerant or in whom IFN-alpha therapy fails. Such therapeutic options should be considered in LCP patients, particularly in countries where IM may not be available.  相似文献   
138.
In Argentina, American Cutaneous Leishmaniasis (ACL) extends up to 29°S in the phytogeographic regions of the Yungas (west), Chaco (center) and Paranaense (east). Since the Phlebotominae vectors of this disease in the western Chaco (dry Chaco) are unknown, in the present work, we studied the natural infection in Phlebotominae by PCR-ERFLP and Dot blot in order to incriminate these organisms as potential vectors. Captures with CDC-type traps were performed monthly in the domicile, the peridomicile and the forest in the Municipio Misión Nueva Pompeya, Chaco, Argentina, in two sites with human cases of ACL: Los Pozos (24°54'S, 61°22'W) and Fortín Arenales (24°58'S, 61°21'W), from November 2006 to December 2007. A total of 1702 Phlebotominae were captured: Mygonemyia migonei (83.8%), cortelezzii complex (11.1%), Mycropigomyia peresi (3.3%), Mycropygomy quinquefer (1.2%), Pintomyia torresi (0.2%) and Nyssomyia neivai (0.2%). Although no significant differences were found in species diversity, there were significant differences in abundance between both sites studied. A total of 80 phlebotomine females were analyzed: 50 of the cortelezzii complex and 30 My. migonei. No intestinal flagellates were observed by light microscopy. Two pools of 10 individuals of the cortelezzii complex of the peridomicile and forest of Fortín Arenales were reactive by PCR and Dot blot for Leishmania (Viannia) braziliensis. In Argentina, Evandromyia cortelezzii has been incriminated as a likely vector of ACL because of its abundance in areas of sporadic outbreaks. In the present work, Ev. cortelezzii females were found naturally infected, thus reinforcing the hypothesis that the members of the cortelezzii complex act as vectors of the disease.  相似文献   
139.
Tropical diseases, mainly leishmaniasis and malaria, increased among Colombian military personnel due to intensive operations in the jungle in the last ten years; as a result the Colombian army developed important preventive strategies for malaria and leishmaniasis. However, no knowledge exists about toxoplasmosis, an emergent disease in military personnel. We compared the prevalence of IgG anti-Toxoplasma antibodies by ELISA and of parasitaemia by a real time PCR assay, in 500 professional soldiers that operated in the jungle with a group of 501 soldiers working in an urban zone (Bogotá). We found that the prevalence was significantly different between both groups of soldiers (80% in soldiers operating in jungle vs. 45% in urban soldiers, adjusted OR 11.4; CI 95%: 3.8-34; p<0.0001). All soldiers operating in the jungle drink unboiled and chlorine untreated lake or river water. In urban soldiers, these risk factors along with eating wild animal meat or eating tigrillo (little spotted cat) were significantly associated with a higher prevalence. Characteristic toxoplasmic choriorretinal lesions were found in 4 soldiers that operated in the jungle (0.8%) and in one urban soldier (0.19%). All soldiers before being deployed in jungle operations should be tested for Toxoplasma antibodies and to receive adequate health information about the routine use of personnel filters to purify their water for consumption.  相似文献   
140.
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