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   865篇
  免费   119篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   60篇
妇产科学   20篇
基础医学   97篇
口腔科学   17篇
临床医学   83篇
内科学   205篇
皮肤病学   28篇
神经病学   85篇
特种医学   85篇
外科学   69篇
综合类   28篇
预防医学   127篇
眼科学   9篇
药学   31篇
中国医学   1篇
肿瘤学   35篇
  2022年   8篇
  2021年   9篇
  2020年   7篇
  2019年   7篇
  2017年   17篇
  2016年   18篇
  2015年   14篇
  2014年   19篇
  2013年   44篇
  2012年   23篇
  2011年   32篇
  2010年   29篇
  2009年   31篇
  2008年   30篇
  2007年   26篇
  2006年   28篇
  2005年   26篇
  2004年   22篇
  2003年   24篇
  2002年   16篇
  2001年   11篇
  2000年   6篇
  1999年   7篇
  1998年   23篇
  1997年   43篇
  1996年   39篇
  1995年   23篇
  1994年   25篇
  1993年   27篇
  1992年   18篇
  1991年   12篇
  1990年   26篇
  1989年   38篇
  1988年   32篇
  1987年   24篇
  1986年   21篇
  1985年   27篇
  1984年   12篇
  1983年   10篇
  1981年   6篇
  1980年   11篇
  1979年   13篇
  1978年   8篇
  1977年   11篇
  1976年   10篇
  1975年   10篇
  1974年   13篇
  1973年   6篇
  1972年   6篇
  1967年   6篇
排序方式: 共有985条查询结果,搜索用时 578 毫秒
1.
2.
Certain groups of patients requiring enteral nutritional support are at increased risk of regurgitation and pulmonary aspiration of feed. Positioning of enteral feeding tubes distal to the pylorus has been advocated as a method of reducing such complications. Various techniques have been suggested to achieve postpyloric siting. Reports have indicated that lengthening the tube or altering the distal end tip configuration, by varying the tip profile or by the addition of a weight, may facilitate spontaneous transpyloric passage of the tube. This prospective controlled clinical study using three new polyurethane tubes demonstrates that the frequency of spontaneous transpyloric passage of the tube is not affected by tip profile or by the addition of a weight. Indeed, with all three tube designs only about one-third had passed spontaneously through the pylorus at 24 hr. Once through the pylorus the unweighted tube stayed in position significantly longer than the weighted tubes (p less than 0.005). We suggest that in those patients requiring post-pyloric feeding, endoscopic or fluoroscopic techniques should be used to position the tubes at the time of insertion, and that an unweighted tube should be used to prolong tube usage.  相似文献   
3.
AD  Giannoukas  N  Labropoulos  FCT  Smith  GS  Venables  JD  Beard  武婕 《中华脑血管病论坛》2005,3(5):555-560
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章.  相似文献   
4.
5.
“维生素AD、铁营养强化奶的研制”研究报告   总被引:1,自引:0,他引:1  
目的:研制维生素AD、铁营养强化奶,用于群体有效防治维生素AD、铁缺乏.方法:应用微胶囊技术科学配方成维生素AD、铁营养粉,添加到鲜牛奶中.结果:工业化生产维生素AD、铁营养强化奶.结论:该产品取得了很好的社会效益和经济效益.  相似文献   
6.
We have reviewed and discussed data concerning the development of hepatobiliary dysfunction in the patient requiring TPN. The data above can be summarised in a short statement--TPN-related hepatobiliary dysfunction is multifactorial. Despite all the factors discussed, the patients underlying disease state and the severity of the illness may be the most significant factor in the development of hepatobiliary dysfunction. With our current state of knowledge it is only possible for the clinician to be aware which of his patients are most likely to develop problems, and to forecast the type of dysfunction that is most likely to occur. There is no treatment--apart from stopping TPN--but there are certain methods by which the incidence and degree of dysfunction may be minimised, or some of the complications (e.g. gallstones) treated. Fortunately in most cases the degree of dysfunction is both self-limiting and reversible on cessation of TPN.  相似文献   
7.
Notifiable disease surveillance systems provide essential data for infectious disease prevention and control programs at the local, state, and national levels. Given that reporting completeness is known to vary considerably, this review identifies methods that can reliably enhance completeness of reporting. These surveillance-related activities include initiating active surveillance when appropriate; implementing automated, electronic laboratory-based reporting; strengthening ties with clinicians and other key partners in notifiable disease reporting; and increasing the use of laboratory diagnostic tests in identifying new cases. Despite ample data in support of these strategies, notifiable disease surveillance continues to receive insufficient attention and resources. Recent attention to public health preparedness provides an opportunity to strengthen notifiable disease surveillance and enhance completeness of reporting.  相似文献   
8.
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi.  相似文献   
9.
Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms.  相似文献   
10.
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