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   51536篇
  免费   3182篇
  国内免费   192篇
耳鼻咽喉   587篇
儿科学   1435篇
妇产科学   1051篇
基础医学   7252篇
口腔科学   4214篇
临床医学   4190篇
内科学   10523篇
皮肤病学   1133篇
神经病学   4054篇
特种医学   1271篇
外国民族医学   2篇
外科学   6140篇
综合类   582篇
一般理论   18篇
预防医学   5744篇
眼科学   724篇
药学   3524篇
中国医学   432篇
肿瘤学   2034篇
  2023年   478篇
  2022年   1083篇
  2021年   1868篇
  2020年   1257篇
  2019年   1571篇
  2018年   1856篇
  2017年   1325篇
  2016年   1398篇
  2015年   1647篇
  2014年   2188篇
  2013年   2575篇
  2012年   3854篇
  2011年   4211篇
  2010年   2162篇
  2009年   1683篇
  2008年   2883篇
  2007年   2848篇
  2006年   2435篇
  2005年   2181篇
  2004年   1883篇
  2003年   1766篇
  2002年   1563篇
  2001年   1105篇
  2000年   1112篇
  1999年   896篇
  1998年   351篇
  1997年   243篇
  1996年   231篇
  1995年   199篇
  1994年   182篇
  1993年   161篇
  1992年   446篇
  1991年   440篇
  1990年   418篇
  1989年   401篇
  1988年   353篇
  1987年   310篇
  1986年   295篇
  1985年   279篇
  1984年   213篇
  1983年   181篇
  1979年   189篇
  1978年   145篇
  1974年   143篇
  1973年   141篇
  1972年   109篇
  1971年   126篇
  1970年   145篇
  1969年   135篇
  1967年   123篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
2.
3.
4.
5.
6.
7.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
8.
The spatial distribution of enteroparasitosis in an indigenous village from Paraná was evaluated to identify areas of risk for these infections. A cross-sectional study (from November 2010 to June 2011) was performed using Three Faecal Test® and Kato &; Katz method and a questionnaire on housing and hygiene conditions was administered. Local geostatistical analyses were performed to determine the spatial distribution of intestinal parasitic infections. The overall prevalence of enteroparasites was 67.2?% (457/680), and the most prevalent taxa were Ascaris lumbricoides (48.8?%) and Trichuris trichiura (44.7?%). The prevalence of heavy infection by soil-transmitted helminths was 3.6?% and the families lived in houses with an average of 5.1 residents and < 2 bedrooms per household. The average number of species per individual present spatial heterogeneity with the highest values (≥0.8) in areas with high clustering of residences. The visualization of the spatial distribution of intestinal parasites in this indigenous village is an important contribution to determining health risk areas and planning decisions and services.  相似文献   
9.
10.

Background Drug-related problems are mostly preventable or predictable circumstances that may impact on health outcomes. Clinical pharmacy activities such as medication therapy management can identify and solve these problems, with potential to improve medication safety and effectiveness. Objective To evaluate ability of medication therapy management service to detect drug-related problems and prevent adverse drug events. This study also aimed to assess the risk factors for drugrelated problem occurrence. Setting Medical intensive care unit of a public tertiary hospital in Brazil. Methods Patients were evaluated by a clinical pharmacist, who provided medication therapy management service. Detected drug-related problems were categorized according to the Pharmaceutical Care Network Europe methodology and analyzed in multinomial regression to identify risk factors. Main outcome measure Potential risk factors for drug-related problem occurrence. Results The proposed medication therapy management service allowed detection of 170 drug-related problems that had potential to reach patients causing harm and other 50 unavoidable adverse events. Drug-related problems identified were more often associated with antibacterial use, caused by improper combinations or inadequate drug dosage. These problems required interventions that were accepted by the multidisciplinary team, resulting in more than 85% adherence and total problem solving. Main risk factors identified were previous diagnosis of kidney injury (OR?=?8.38), use of midazolam (OR?=?7.96), furosemide (OR?=?5.87) and vancomycin (OR?=?4.82). Conclusion Medication therapy management proved to be an effective method not only for drug-related problem detection, but also for adverse drug event prevention, contributing to improve patient safety.

  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