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   1045篇
  免费   94篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   25篇
妇产科学   18篇
基础医学   157篇
口腔科学   21篇
临床医学   139篇
内科学   300篇
皮肤病学   39篇
神经病学   37篇
特种医学   87篇
外国民族医学   1篇
外科学   61篇
综合类   44篇
一般理论   1篇
预防医学   40篇
眼科学   32篇
药学   70篇
中国医学   1篇
肿瘤学   65篇
  2022年   15篇
  2021年   17篇
  2020年   10篇
  2019年   20篇
  2018年   17篇
  2017年   17篇
  2016年   16篇
  2015年   22篇
  2014年   28篇
  2013年   31篇
  2012年   18篇
  2011年   42篇
  2010年   36篇
  2009年   35篇
  2008年   31篇
  2007年   30篇
  2006年   36篇
  2005年   21篇
  2004年   24篇
  2003年   29篇
  2002年   24篇
  2001年   15篇
  2000年   24篇
  1999年   27篇
  1998年   27篇
  1997年   19篇
  1996年   26篇
  1995年   22篇
  1994年   30篇
  1993年   32篇
  1992年   23篇
  1991年   15篇
  1990年   13篇
  1989年   21篇
  1988年   22篇
  1987年   21篇
  1986年   17篇
  1985年   24篇
  1984年   10篇
  1983年   14篇
  1982年   13篇
  1981年   19篇
  1980年   15篇
  1979年   22篇
  1978年   13篇
  1977年   14篇
  1976年   10篇
  1975年   16篇
  1957年   10篇
  1949年   9篇
排序方式: 共有1140条查询结果,搜索用时 31 毫秒
1.
Secretory antibodies protect mucosal surfaces against transmission of many viruses. Human T-lymphotropic Virus, Type I (HTLV-I) is transmitted via blood products and via sexual contact across mucosal surfaces. We investigated the presence of HTLV-I-specific antibodies in whole saliva samples from 10 seronegative and 28 seropositive volunteers from a hospital in southern Japan. Antibodies directed to HTLV-I antigens were found in the salivas from 22 of 28 (79%) of the seropositive subjects. None of the seronegative individuals showed evidence of salivary antibodies. Antibodies directed to the envelope antigens of the virus were found in 21 of 22 positive saliva samples. Secretory antibodies may be important in preventing mucosal transmission.  相似文献   
2.
3.
Objective: The aim of this study was to determine the prevalence of low back pain (LBP) in a primary care setting population and examine its association with the symptoms of depression and somatization. Methods: This is a cross‐sectional study, utilising a survey carried out in primary health care clinics (PHCs) in Al‐Ain, United Arab Emirates (UAE). A multistage stratified sampling design was used and a representative sample of 1304 UAE nationals aged 18–65 years who attended PHC clinics for any reason were included and 1103 (84.5%) subjects agreed to participate and responded to the questionnaire during a period from June 2001 to January 2002. A specially designed questionnaire with three parts was used for the data collection: socio‐demographic information of the studied subjects, modified version of the Roland‐Morris scale for evaluating back‐related functional disability and SCL‐90 R for depression and somatization subscales was used to assess depressive and somatic symptoms. Results: Of the total number of subjects surveyed (1103), 586 (53.1%) were men and 517 (46.9%) women. The mean age was 34.9 ± 13.4 years for men and 33.5 ± 11.8 years for women. The prevalence of LBP in the studied subjects was 64.7% (95% CI, 60.7–68.5] with 46.7% among men and 53.3% among women. There were a significant differences between the subjects with LBP and without LBP with respect to gender (P < 0.001), body mass index (BMI) (P < 0.001), occupational status (P < 0.001) and living environment (P = 0.016). Functional disability was higher in patients with LBP. Young patients in aged 15–34 years, patients with preparatory/secondary educational level and students showed higher depressive symptoms. A similar pattern was found in patients with somatic symptoms. Factor analysis revealed a strong association between depression and somatization in LBP patients. Conclusions: Functional disability was higher in with LBP. Furthermore, symptoms of depression and somatization are prevalent among LBP patients.  相似文献   
4.
The community-based course presented is a longitudinal course running through four semesters in the Faculty of Medicine, University of Gezira, Sudan. Students combine their regular work in primary health care centres with attachments to a number of families in Wad Medani town. They continue to visit these families regularly throughout their entire medical course with the aim of studying them and helping them with some of their medical and psychosocial problems.  相似文献   
5.
6.
Abstract  We previously demonstrated that cytomegalovirus (CMV) infection enhanced perivascular inflammation in rat aortic allografts. In this study, we investigated the relationship between the CMV infection load and the magnitude of perivasculitis (chronic rejection) in aortic transplants. Rats received or-thotopic abdominal aortic grafts, different degrees of total body irradiation (TBI) for immunosuppres-sion and CMV inoculation. The spleens of the rats receiving 5 Gy of TBI contained more infectious virus and viral antigens than those of rats receiving 3 Gy of TBI or no TBI. Although the number of inflammatory cells infiltrating the perivascular area was decreased after TBI, CMV infection resulted in increased perivasculitis in rats that received 5 Gy of TBI as compared to non-infected animals. This virus-induced effect was characterized predominantly by an increased T-cell infiltration, including CD4 and CD8 T-cells. It is concluded that an enhanced systemic CMV infection during severe immunosuppressive therapy can accelerate the development of chronic rejection, which seems to be mediated mainly by T-cells.  相似文献   
7.
8.
A 48‐year‐old male patient with long‐standing ulcerative colitis since February 2001 which was diagnosed by endoscopy, developed acute digital ischemia affecting both hands with fixed colour changes in the left index finger which was followed shortly by digital ulceration. Magnetic resonance angiography (MRA) of both upper limbs showed evidence of vasculitis affecting digital arterioles on both sided and right subclavian occlusion. The patient received pulse methylprednisolone followed by cyclophosphamide pulse therapy, the latter continuing on a monthly basis for 6 months with appreciable improvement and remission of the vasculitic process; follow‐up MRA showed reperfusion of the previously occluded subcalvian artery. To the authors’ knowledge vasculitis complicating the course of ulcerative colitis is a rare association and is only sporadically reported in the literature. This rare entity should be diagnosed early and aggressively treated; MRA is a very promising diagnostic tool that is suitable for both diagnosis and follow‐up of patients with this rare entity.  相似文献   
9.
10.
OBJECTIVE: Few studies have been able to track the genetic diversity of HIV-1 viruses in human populations over time. We analyzed the molecular evolution of subtype A over a 10-year period, in a cohort of female sex workers with a known time of infection. STUDY DESIGN/METHODS: We amplified and sequenced the C2-V3 region of the surface envelope glycoprotein from 73 HIV-1-infected women, infected between 1987-1997. RESULTS: Fifty-one patients were infected by subtype A viruses. The viruses demonstrated significant diversification (p < 0.001) with mean genetic distance increasing from 8.6% in 1989 to 15.9% in 1997. The slope of the fitted curve suggested a rate of diversification of 0.7% per year. The majority of subtype A viruses clustered with HIV-1 subtype A/G recombinant form (IbNG). CONCLUSION: The genetic diversity of HIV-1 subtype A infections doubled over the first 10 years of this high risk population's epidemic, suggesting that implementation of vaccines early in the epidemic may have a higher likelihood of success based on levels of genetic diversity. The A/G recombinant form (IbNG) has taken epidemic proportions in West Africa. This is of particular importance in understanding the epidemiology of HIV-1 subtypes in Africa and to further dissect the potential phenotypic and biological characteristics of these viruses.  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