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   358402篇
  免费   23291篇
  国内免费   2741篇
耳鼻咽喉   8480篇
儿科学   12355篇
妇产科学   7266篇
基础医学   30282篇
口腔科学   7049篇
临床医学   40956篇
内科学   82023篇
皮肤病学   12461篇
神经病学   32285篇
特种医学   15768篇
外国民族医学   25篇
外科学   72259篇
综合类   1389篇
现状与发展   72篇
一般理论   46篇
预防医学   17650篇
眼科学   8394篇
药学   14434篇
  3篇
中国医学   444篇
肿瘤学   20793篇
  2024年   1488篇
  2023年   5962篇
  2022年   2132篇
  2021年   4718篇
  2020年   7261篇
  2019年   3771篇
  2018年   10691篇
  2017年   9990篇
  2016年   12093篇
  2015年   12384篇
  2014年   19746篇
  2013年   21888篇
  2012年   14809篇
  2011年   14404篇
  2010年   15565篇
  2009年   18355篇
  2008年   14194篇
  2007年   13407篇
  2006年   15766篇
  2005年   13533篇
  2004年   12370篇
  2003年   11187篇
  2002年   11143篇
  2001年   10486篇
  2000年   9797篇
  1999年   9070篇
  1998年   5411篇
  1997年   4933篇
  1996年   4493篇
  1995年   4132篇
  1994年   2807篇
  1993年   2371篇
  1992年   4101篇
  1991年   4045篇
  1990年   3666篇
  1989年   3608篇
  1988年   3163篇
  1987年   2972篇
  1986年   2907篇
  1985年   2657篇
  1984年   2077篇
  1983年   1750篇
  1979年   1933篇
  1978年   1501篇
  1977年   1381篇
  1975年   1507篇
  1974年   1533篇
  1973年   1441篇
  1972年   1534篇
  1971年   1368篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Background: Social media are currently considered as a potential complementary source of knowledge for drug safety surveillance. Our primary objective was to estimate the frequency of adverse drug reactions (ADRs) experienced by Twitter users. Our secondary objective was to determine whether tweets constitute a valuable and informative source of data for pharmacovigilance purposes, despite limitations on character number per tweet.

Research design and methods: We selected a list of 33 drugs subject to careful monitoring due to safety concern in France and Europe, and extracted tweets using the streaming API from 30 September 2014 to 5 April 2015. Two pharmacovigilance centers classified these tweets manually as potential ADR case reports.

Results: Among 10,534 tweets, 848 (8.05%) implied or mentioned an ADR without meeting the four FDA criteria required for reporting an ADR, and 289 (2.74%) tweets were classified as ‘case reports.’ Among them 20 (7.27%) tweets mentioned an unexpected ADR and 33 (11.42%) tweets mentioned a serious ADR.

Conclusions: With the use of dedicated tools, Twitter could become a complementary source of information for pharmacovigilance, despite a major limitation regarding causality assessment of ADRs in individual tweets, which may improve with the new limitation to 280 characters per tweet.  相似文献   

13.
14.
15.
Archives of Women's Mental Health - Pregnancy and the postpartum period involve numerous physiological adaptations that enable the development and survival of the offspring. A distinct neural...  相似文献   
16.
ObjectivesHigh-quality diagnosis of bloodstream infections (BSI) is important for successful patient management. As knowledge on current practices of microbiological BSI diagnostics is limited, this project aimed to assess its current state in European microbiological laboratories.MethodsWe performed an online questionnaire-based cross-sectional survey comprising 34 questions on practices of microbiological BSI diagnostics. The ESCMID Study Group for Bloodstream Infections, Endocarditis and Sepsis (ESGBIES) was the primary platform to engage national coordinators who recruited laboratories within their countries.ResultsResponses were received from 209 laboratories in 25 European countries. Although 32.5% (68/209) of laboratories only used the classical processing of positive blood cultures (BC), two-thirds applied rapid technologies. Of laboratories that provided data, 42.2% (78/185) were able to start incubating BC in automated BC incubators around-the-clock, and only 13% (25/192) had established a 24-h service to start immediate processing of positive BC. Only 4.7% (9/190) of laboratories validated and transmitted the results of identification and antimicrobial susceptibility testing (AST) of BC pathogens to clinicians 24 h/day. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry from briefly incubated sub-cultures on solid media was the most commonly used approach to rapid pathogen identification from positive BC, and direct disc diffusion was the most common rapid AST method from positive BC.ConclusionsLaboratories have started to implement novel technologies for rapid identification and AST for positive BC. However, progress is severely compromised by limited operating hours such that current practice of BC diagnostics in Europe complies only partly with the requirements for optimal BSI management.  相似文献   
17.
Many transplantation centers routinely collect 1 or more autologous peripheral blood stem cell (PBSC) grafts in patients with hemato-oncologic and autoimmune disorders. However, subsequent high-dose chemotherapy and autologous blood stem cell transplantation (ABSCT) are often not performed, for various reasons. Currently, little is known about the actual utilization rate of stored PBSCs. We retrospectively analyzed the collection, storage, and disposal practices of PBSC products from a large cohort of patients (n?=?1020) with hematologic, oncologic, and autoimmune disorders at our institution over a 12-year period. Patients with multiple myeloma were excluded. Based on our institution-specific charges, we estimated the costs for PBSC collection/processing and storage. The median number of sufficient PBSC collections per patient in the whole cohort was 2 (range, 1 to 6). We could demonstrate that only 67% of all patients who had collected sufficient PBSCs for transplantation actually underwent ABSCT, and only a small minority of all patients (4%) underwent multiple ABSCTs. The actual use of the stored PBSC grafts varied among disease entities from >80% to 0%. From a retrospective standpoint, the collected and discarded (definitively not used) or stored (potentially not used) cryostored PBSCs were associated with considerable costs of collection, cryopreservation, and long-term cryostorage. Although keeping open the therapeutic option for future transplantations may be important, there is currently a huge discrepancy between collection/storage practices and actual utilization of the cryopreserved PBSCs, at a considerable cost and strain on patients. Our study provides a rationale for reevaluating the present standards.  相似文献   
18.
The anti-epileptic drugs phenobarbital and valproic acid have an extremely strong negative effect on cognitive processes such as learning and memory in the developing brain. We examined whether or not curcumin has protective effects on neuronal injury caused by these drugs in the developing rat brain. Young male Wistar rats were studied in two groups, a 7 days old and a 14 days old group (35 rats in each). Both groups were then divided into 7 sub-groups as the control, curcumin, dimethylsulfoxide, phenobarbital, valproic acid, phenobarbital + curcumin, and valproic acid + curcumin groups (n = 5 in each group). At 24 h after the intraperitoneal injection of the compounds, the rats were sacrificed, and the hippocampal tissue was subjected to stereological analysis with the optical fractionation method. Total numbers of neurons in the hippocampus of the 7 days old and 14 days old rats were calculated. It was found that treatment with phenobarbital resulted in a loss of 43% of the neurons, and valproic acid induced a loss of 57% of the neurons in the 7 days old rats. Curcumin prevented this loss significantly with only 19% in the phenobarbital group and 41% in the valproic acid group. In the 14 days old rat groups, phenobarbital was found to reduce the number of neurons by 30%, and valproic acid reduced it by 38%. Curcumin treatment limited neuronal loss to 3% in the phenobarbital + curcumin group and 10% in the valproic acid + curcumin group. These data strongly indicate that curcumin is a protective agent and prevents hippocampal neuronal damage induced by phenobarbital and valproic acid treatment.  相似文献   
19.
20.
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