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   2849篇
  免费   194篇
  国内免费   5篇
耳鼻咽喉   56篇
儿科学   135篇
妇产科学   102篇
基础医学   305篇
口腔科学   253篇
临床医学   282篇
内科学   539篇
皮肤病学   45篇
神经病学   211篇
特种医学   84篇
外科学   361篇
综合类   14篇
一般理论   1篇
预防医学   209篇
眼科学   123篇
药学   155篇
中国医学   3篇
肿瘤学   170篇
  2023年   53篇
  2022年   23篇
  2021年   123篇
  2020年   86篇
  2019年   134篇
  2018年   98篇
  2017年   81篇
  2016年   102篇
  2015年   118篇
  2014年   149篇
  2013年   199篇
  2012年   227篇
  2011年   231篇
  2010年   126篇
  2009年   120篇
  2008年   183篇
  2007年   195篇
  2006年   148篇
  2005年   154篇
  2004年   133篇
  2003年   100篇
  2002年   115篇
  2001年   22篇
  2000年   24篇
  1999年   22篇
  1998年   12篇
  1997年   12篇
  1995年   3篇
  1994年   7篇
  1993年   5篇
  1992年   3篇
  1991年   5篇
  1990年   2篇
  1989年   3篇
  1988年   4篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1981年   2篇
  1980年   4篇
  1979年   1篇
  1975年   1篇
  1972年   2篇
  1970年   1篇
  1967年   2篇
  1966年   2篇
  1960年   2篇
  1959年   1篇
  1935年   1篇
排序方式: 共有3048条查询结果,搜索用时 15 毫秒
1.
2.
3.
ObjectivesTo describe recent trends in advanced imaging and hospitalization of emergency department (ED) syncope patients, both considered “low-value”, and examine trend changes before and after the publication of American College Emergency Physician (ACEP) syncope guidelines in 2007, compared to conditions that had no changes in guideline recommendations.MethodsWe analyzed 2002–2015 National Hospital Ambulatory Medical Care Survey data using an interrupted-time series with comparison series design. The primary outcomes were advanced imaging among ED visits with principal diagnosis of syncope and headache and hospitalization for ED visits with principal diagnosis of syncope, chest pain, dysrhythmia, and pneumonia. We adjusted annual imaging and hospitalization rates using survey-weighted multivariable logistic regression, controlling for demographic and visit characteristics. Using adjusted outcomes as datapoints, we compared linear trends and trend changes of annual imaging and hospitalization rates before and after 2007 with aggregate-level multivariable linear regression.ResultsFrom 2002 to 2007, advanced imaging rates for syncope increased from 27.2% to 42.1% but had no significant trend after 2007 (trend change: ?3.1%; 95%CI ?4.7, ?1.6). Hospitalization rates remained at approximately 37% from 2002 to 2007 but declined to 25.7% by 2015 (trend change: ?2.2%; 95%CI ?3.0, ?1.4). Similar trend changes occurred among control conditions versus syncope, including advanced imaging for headache (difference in trend change: ?0.6%; 95%CI ?2.8, 1.6) and hospitalizations for chest pain, dysrhythmia, and pneumonia (differences in trend changes: 0.1% [95%CI ?1.9, 2.0]; ?0.9% [95%CI ?3.1, 1.3]; and ?1.2% [95%CI ?5.3, 2.9], respectively).ConclusionsBefore and after the release of 2007 ACEP syncope guidelines, trends in advanced imaging and hospitalization for ED syncope visits had similar changes compared to control conditions. Changes in syncope care may, therefore, reflect broader practice shifts rather than a direct association with the 2007 ACEP guideline. Moreover, utilization of advanced imaging remains prevalent. To reduce low-value care, policymakers should augment society guidelines with additional policy changes such as reportable quality measures.  相似文献   
4.
The main clinical features of tyrosinemia type 1 usually appear in the first months of life, including fever, diarrhea, vomiting, liver involvement, growth failure, and renal proximal tubulopathy with subsequent hypophosphatemic rickets. An early diagnosis is crucial in order to provide specific management and to prevent complications. Here, we report on two cases referred primarily to pediatric nephrologists for the diagnosis of “neonatal tubulopathy” and management of “X-linked hypophosphatemia (XLH),” respectively. Our aim is to emphasize that (1) even a mixed tubulopathy can reveal tyrosinemia, and (2) tyrosinemia is a classic differential diagnosis of XLH that should not be forgotten, especially in the era of the anti-FGF23 burosumab.  相似文献   
5.
6.
Taurodontism is a rare embryologic anomaly of teeth, defined by an apical displacement of the furcation of roots and enlarged pulp chambers. Taurodontism has been classified as hypo‐, meso‐ or hypertaurodontism according to the severity of the anomaly. The aim of this case report was to illustrate a clinical case with multiple bilateral taurodonts and to describe the endodontic management of the hypertaurodontic mandibular left second molar with a C‐shaped canal and extensive dental pulp calcifications. A healthy 20‐year‐old male patient was referred for the endodontic treatment of his lower left second molar. Cone beam computed tomography revealed a C‐shaped root canal configuration and several dental pulp calcifications in this tooth. The endodontic treatment was performed in two appointments under an operating dental microscope. A panoramic radiograph, made during the 18 months follow‐up appointment, revealed nine other taurodontic molars, most of them associated with dental pulp calcifications.  相似文献   
7.
8.
9.
Toys are a reflection of the compounds used frequently in manufacturing. Allergic contact dermatitis to potties, metal toys, and children's jewelry is well known, however, there is a broad range of skin risks in toys. With the objective to identify and publicize the associated risk of contact dermatitis in children's toys, we have searched the PubMed database from creation to September 9, 2019. Studies were eligible if they reported a new case of contact dermatitis secondary to interaction with a toy in patients from birth to 18 years of age. A toy was defined as something children interact with for entertainment during leisure time. In this review of the PubMed database we filtered by age and language which may have prevented us from detecting cases in adults that could be extrapolated to children. In addition, several articles were excluded based on title alone. A total of 1312 articles were identified and reviewed manually for inclusion criteria. Review of the articles found 25 original articles for consideration. Several toys were found to be associated with contact dermatitis. These included electronics, toy cars, costume jewelry, bicycles, sqwish balls, slime, Play-Doh, and plasticine. Electronics such as video game controllers, cellphones, iPads, and computers were implicated. In conclusion, there is still an unmet need for observation of this segment of industry for labeling of contents and ongoing surveillance.  相似文献   
10.
Mild-traumatic brain injury (mTBI) represents ~80% of all emergency room visits and increases the probability of developing long-term cognitive disorders in children. To date, molecular and cellular mechanisms underlying post-mTBI cognitive dysfunction are unknown. Astrogliosis has been shown to significantly alter astrocytes' properties following brain injury, potentially leading to significant brain dysfunction. However, such alterations have never been investigated in the context of juvenile mTBI (jmTBI). A closed-head injury model was used to study jmTBI on postnatal-day 17 mice. Astrogliosis was evaluated using glial fibrillary acidic protein (GFAP), vimentin, and nestin immunolabeling in somatosensory cortex (SSC), dentate gyrus (DG), amygdala (AMY), and infralimbic area (ILA) of prefrontal cortex in both hemispheres from 1 to 30 days postinjury (dpi). In vivo T2-weighted-imaging (T2WI) and diffusion tensor imaging (DTI) were performed at 7 and 30 dpi to examine tissue level structural alterations. Increased GFAP-labeling was observed up to 30 dpi in the ipsilateral SSC, the initial site of the impact. However, vimentin and nestin expression was not perturbed by jmTBI. The morphology of GFAP positive cells was significantly altered in the SSC, DG, AMY, and ILA up to 7 dpi that some correlated with magnetic resonance imaging changes. T2WI and DTI values were significantly altered at 30 dpi within these brain regions most prominently in regions distant from the impact site. Our data show that jmTBI triggers changes in astrocytic phenotype with a distinct spatiotemporal pattern. We speculate that the presence and time course of astrogliosis may contribute to pathophysiological processes and long-term structural alterations following jmTBI.  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