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   490篇
  免费   19篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   11篇
妇产科学   11篇
基础医学   50篇
口腔科学   15篇
临床医学   68篇
内科学   88篇
皮肤病学   4篇
神经病学   30篇
特种医学   12篇
外科学   125篇
综合类   12篇
预防医学   27篇
眼科学   3篇
药学   23篇
肿瘤学   28篇
  2023年   3篇
  2022年   8篇
  2021年   29篇
  2020年   10篇
  2019年   19篇
  2018年   21篇
  2017年   6篇
  2016年   10篇
  2015年   24篇
  2014年   20篇
  2013年   20篇
  2012年   61篇
  2011年   36篇
  2010年   14篇
  2009年   21篇
  2008年   33篇
  2007年   18篇
  2006年   13篇
  2005年   15篇
  2004年   19篇
  2003年   15篇
  2002年   9篇
  2001年   6篇
  1999年   12篇
  1996年   2篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1990年   2篇
  1988年   2篇
  1986年   4篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1979年   5篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1975年   3篇
  1974年   3篇
  1973年   2篇
  1972年   6篇
  1971年   2篇
  1969年   2篇
  1968年   2篇
  1967年   2篇
  1966年   4篇
  1965年   1篇
排序方式: 共有510条查询结果,搜索用时 62 毫秒
1.
2.
In Karachi, Pakistan, a South Asian megacity with a high prevalence of tuberculosis (TB) and low HIV prevalence, we assessed the effectiveness of fluoroquinolone-based preventive therapy for drug-resistant (DR) TB exposure. During February 2016–March 2017, high-risk household contacts of DR TB patients began a 6-month course of preventive therapy with a fluoroquinolone-based, 2-drug regimen. We assessed effectiveness in this cohort by comparing the rate and risk for TB disease over 2 years to the rates and risks reported in the literature. Of 172 participants, TB occurred in 2 persons over 336 person-years of observation. TB disease incidence rate observed in the cohort was 6.0/1,000 person-years. The incidence rate ratio ranged from 0.29 (95% CI 0.04–1.3) to 0.50 (95% CI 0.06–2.8), with a pooled estimate of 0.35 (95% CI 0.14–0.87). Overall, fluoroquinolone-based preventive therapy for DR TB exposure reduced risk for TB disease by 65%.  相似文献   
3.
A highly sensitive assay for mammalian lysosomal pepstatin-insensitive proteinase (LPIP) is described using a synthetic peptide substrate coupled to aminotrifluoromethyl coumarin (AFC). LPIP is an endocarboxyl proteinase which has specific sequence requirements of Phe-Phe around the carboxyl terminal. This HPLC based assay can detect patients suffering from late-infantile neuronal ceroid lipofuscinosis (LINCL) and also heterozygote carriers in cultured lymphoid cells and skin fibroblasts. None of the patients analyzed had detectable enzyme activity confirming the defective gene product, while carriers had about 50% activity when compared with the normal controls. Neurological controls comprised of patients with other neurodegenerative disorders have LPIP activities similar to normal controls. LPIP activity is also detectable in amniocytes and chorionic villi. Thus the assay reported can also be used for prenatal diagnosis of LINCL.  相似文献   
4.
The effect of aorto-coronary bypass graft surgery (CBG) upon regional myocardial perfusion (RMP) was studied in 23 patients using thallium-201 myocardial perfusing imaging after exercise. We compared the changes in RMP with the clinical status and ECG's during graded treadmill exercise (GTX) before and after CBG. After CBG, the New York Heart Association's "functional class" improved from 3.2 +/- 0.1 (mean +/- SE) to 1.2 +/- 0.2, p less than 0.005. The GTX performance of the patients was also significantly improved postoperatively as judged by the total exercise time (11.7 +/- 0.6 min postop, compared with 7.2 +/- 0.5 min preop; p less than 0.005). Postoperative improved Tl-201 scintigrams were observed in 19 patients, but in only nine patients did the perfusion distribution return to normal. Thus, Tl-201 exercise scintigrams following CBG demonstrate improved RMP in most patients. Failure of regional myocardial perfusion to improve postoperatively, however, does not preclude marked alleviation of angina and improved exercise tolerance.  相似文献   
5.
6.
7.

While there is evidence of morbidity compression in many countries, temporal patterns of non-communicable diseases (NCDs) in developing countries, such as India, are less clear. Age at onset of disease offers insights to understanding epidemiologic trends and is a key input for public health programs. Changes in age at onset and duration of major NCDs were estimated for 2004 (n = 38,044) and 2018 (n = 43,239) using health surveys from the India National Sample Survey (NSS). Survival regression models were used to compare trends by sociodemographic characteristics. Comparing 2004 to 2018, there were reductions in age at onset and increases in duration for overall and cause-specific NCDs. Median age at onset decreased for NCDs overall (57 to 53 years) and for diabetes, hypertension, heart disease, asthma, mental diseases, eye disease, and bone disease in the range of 2–7 years and increased for cancer, neurological disorders, some genitourinary disorders, and injuries/accidents in the range of 2–14 years. Hazards of NCDs were higher among females for cancers (HR 1.51, 95% CI 1.19–1.90) and neurological disorders (HR 1.18, 95% CI 1.06–1.32) but lower for heart diseases (HR 0.88, 95% CI 0.79–0.97) and injuries/accidents (HR 0.87, 95% CI 0.77–0.99). Hazards were greater among those with lower educational attainment at younger ages and higher educational attainment later in life. Unlike many countries, chronic disease morbidity may be expanding in India for many chronic diseases, indicating excess strain on the health system. Public health programs should focus on early diagnosis and prevention of NCDs.

  相似文献   
8.
The present study has been carried out in the Ponda watershed of district Rajouri (J&K), northwestern Himalaya to analyze local importance of tree species by quantitative ethnobotanical approach and their status of availability in the study area. Data was analyzed using relative frequency of citation (RFC) and use value (UV) index along with Pearson and Spearman correlation coefficients. A total of 34 tree species were encountered represented by 31 genera and 22 families. All identified tree species were classified into 10 general use categories. As per indigenous use, 27 tree species are exploited for firewood followed by 15 for fodder, 12 each for fruits and making agriculture tools whereas very few tree species are being utilized by local people for various other uses. The UV and RFC of different tree species ranged from 0.02 to 0.12 and 0.04 to 0.80, respectively. The Pearson correlation coefficient was found to be higher (0.60) than the Spearman’s rank correlation (0.54), which reflects high linear relationship as compared to monotonic relationship between RFC and UV. The present study showed that Pinus roxburghii was an abundant species, whereas 3 tree species, i.e. Juglans regia, Ficus religiosa and Ulmus wallichiana were observed to be rare. However, according to the IUCN conservation status of the various trees observed in the study area, Juglans regia and Ulmus wallichiana are near threatened and vulnerable species, respectively, which are also exploited for their multiple uses by the locals.  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