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   717篇
  免费   60篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   45篇
妇产科学   13篇
基础医学   87篇
口腔科学   11篇
临床医学   65篇
内科学   184篇
皮肤病学   31篇
神经病学   19篇
特种医学   83篇
外科学   80篇
综合类   23篇
预防医学   22篇
眼科学   7篇
药学   44篇
中国医学   1篇
肿瘤学   62篇
  2021年   5篇
  2020年   3篇
  2019年   4篇
  2018年   2篇
  2017年   8篇
  2016年   11篇
  2015年   14篇
  2014年   18篇
  2013年   27篇
  2012年   23篇
  2011年   23篇
  2010年   33篇
  2009年   37篇
  2008年   41篇
  2007年   30篇
  2006年   26篇
  2005年   26篇
  2004年   25篇
  2003年   25篇
  2002年   20篇
  2001年   16篇
  2000年   2篇
  1999年   9篇
  1998年   23篇
  1997年   43篇
  1996年   31篇
  1995年   21篇
  1994年   25篇
  1993年   23篇
  1992年   12篇
  1991年   9篇
  1990年   10篇
  1989年   33篇
  1988年   14篇
  1987年   12篇
  1986年   15篇
  1985年   17篇
  1984年   8篇
  1982年   3篇
  1981年   5篇
  1980年   8篇
  1979年   6篇
  1978年   5篇
  1977年   10篇
  1976年   5篇
  1975年   5篇
  1956年   1篇
  1955年   1篇
  1932年   1篇
  1929年   1篇
排序方式: 共有780条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
4.
“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   
5.
Spontaneous EDTA-independent cold platelet agglutination is a rare phenomenon that produces pseudothrombocytopenia when blood samples are analyzed in automated cell counters. We report a case of platelet cold agglutinins and an analysis by flow cytometry. A 49 year old woman presented with abnormal vaginal bleed secondary to uterine fibroids. Platelet clumping was observed in blood samples taken in EDTA-, heparin- and citrate-containing tubes. In flow cytometric tests, patient serum agglutinated 16% of normal platelets at 22 degrees C, and 7% of platelets after incubation at 37 degrees C; in contrast, 3% and < 1% of platelets were agglutinated at 22 and 37 degrees C, respectively, after incubation with normal serum. Minimal agglutination (< 10%) was observed with patient serum at a titre of 1:5 or at temperatures > 30 degrees C. After incubation at 4 degrees C, IgM antibody and C3 were increased on the patient's platelets; no significant amount of IgM or C3 was detected on normal platelets. The specificity of the platelet cold agglutinin was determined by competitive inhibition by monoclonal anti-CD41(GPIIbIIIa). Before the addition of monoclonal antibody, patient's serum agglutinated 16% of normal platelets at 22 degrees C; after addition of anti-CD41 only 2% of the platelets were agglutinated. This blocking effect was not observed with anti-CD42. The patient's platelets functioned normally as determined by CD62 and CD63 expression in response to thrombin, normal platelet aggregation in response to collagen, ADP, and ristocetin, and a normal template bleeding time. In summary, platelet agglutination by a platelet cold agglutinin was quantitated by flow cytometry, the responsible antibody was characterized as a low titre IgM with minimal activity > 30 degrees C, and competitive binding studies supported the GPIIbIIIa complex as the binding site for the antibody. Since the antibody did not affect platelet function, we believe that these patients will not suffer complications from their platelet cold agglutinin, but it could pose a problem under circumstances such as cardiac surgery with hypothermia.  相似文献   
6.
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   
7.
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   
8.
A number of studies have shown that ultrasound has an advantage over physical examination in the diagnosis of acute appendicitis. Most of these studies were conducted by experts in the field of ultrasonography. In this study the influence of experience on the results of the sonography of actue appendicitis were evaluated. All 203 patients admitted to our unit between December 1990 and December 1992 were examined physically and sonographically by a team of surgeons consisting of one experienced sonographer and six inexperienced surgical trainees. Laparotomy was performed in 136 patients (46%). Appendicitis was demonstrated histologically in 119 cases (39.4%). Initial clinical findings were positive in 87 (28.8%). Sonography was positive in 119 patients (39.4%). The 163 patients not operated on demonstrated other pathology on ultrasound in 60 cases (19.9%). The rate of negative laparotomies amounted to 7.2% in our study. Sensitivity and specificity for the sonographic diagnosis were 92% and 95%, respectively. They were only 81% and 80% for physical examination. Overall accuracy was 92% for sonography. Sensitivity and specificity for the inexperienced surgeons were 87% and 93%, respectively, while the experienced surgeon reached values of 97% and 98%, respectively. The results of both groups are comparable with values in the literature, suggesting that ultrasound evaluation of appendicitis is not a diagnostic tool limited to a few experienced sonographers.  相似文献   
9.
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