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   2283篇
  免费   134篇
  国内免费   2篇
耳鼻咽喉   7篇
儿科学   105篇
妇产科学   56篇
基础医学   361篇
口腔科学   21篇
临床医学   213篇
内科学   576篇
皮肤病学   42篇
神经病学   249篇
特种医学   94篇
外科学   174篇
综合类   18篇
一般理论   1篇
预防医学   129篇
眼科学   59篇
药学   167篇
中国医学   5篇
肿瘤学   142篇
  2023年   7篇
  2022年   21篇
  2021年   43篇
  2020年   25篇
  2019年   35篇
  2018年   35篇
  2017年   41篇
  2016年   51篇
  2015年   59篇
  2014年   91篇
  2013年   108篇
  2012年   130篇
  2011年   166篇
  2010年   98篇
  2009年   85篇
  2008年   139篇
  2007年   166篇
  2006年   139篇
  2005年   140篇
  2004年   136篇
  2003年   140篇
  2002年   107篇
  2001年   18篇
  2000年   13篇
  1999年   24篇
  1998年   34篇
  1997年   27篇
  1996年   31篇
  1995年   25篇
  1994年   27篇
  1993年   20篇
  1992年   16篇
  1991年   7篇
  1990年   8篇
  1989年   12篇
  1988年   7篇
  1987年   9篇
  1986年   10篇
  1985年   8篇
  1983年   9篇
  1982年   6篇
  1981年   15篇
  1980年   11篇
  1978年   9篇
  1977年   11篇
  1976年   7篇
  1975年   6篇
  1974年   15篇
  1973年   8篇
  1968年   8篇
排序方式: 共有2419条查询结果,搜索用时 0 毫秒
31.
32.
B-type natriuretic peptide (BNP; Abbott Diagnostics) and N-terminal proBNP (NT-proBNP, Roche Diagnostics) were compared in consecutive samples of 458 patients (mean age 60 years+/-16 years; 159 female, 299 male) sent for NT-proBNP measurement to investigate influences on both markers. BNP and NT-proBNP showed a close correlation with each other (r=0.89, p<0.0001). Using age- and gender-adjusted upper reference values the inter-rater agreement of both parameters was satisfactory (83%, Cohen's kappa coefficient=0.7). The combination of normal BNP and elevated NT-proBNP was significantly more frequent than vice versa (61 vs. 16 patients), and a calculated glomerular filtration rate<60 ml/min/1.73 m(2) was found in 39% of these patients. Multiple linear regression analysis revealed a significant influence of a reduced ejection fraction (<50%), renal dysfunction (calculated glomerular filtration rate<60 ml/min/1.73 m(2)), anemia, hypertension, age, and gender on both BNP and NT-proBNP. In conclusion, despite a close correlation and a satisfactory agreement between both markers in classification, frequent discrepancies in individual patients demonstrate that both markers are clinically not completely equivalent.  相似文献   
33.
34.
35.
36.
The aims of this study were to externally validate the OroGrams (oropharyngeal cancer survival calculator) nomogram in a Scottish cohort with high endemic smoking rates, and to compare survival rates with the original validation cohort. A retrospective cohort study in Greater Glasgow and Clyde ENT and OMFS departments was performed to investigate survival outcomes of patients with oropharyngeal squamous cell carcinoma (OPSCC) from January 2012 - December 2017. The main outcome measures were progression-free (PFS) and overall survival (OS), and Kaplan Meier curves. The predictive accuracy of OroGrams was investigated for survival probabilities at one, three, and five years. Smoking and HPV-negative cancer rates were significantly higher in Scottish patients than in the UK consortium cohort. A greater proportion of Scottish patients had advanced UICC8 stages. PFS in patients with HPV-negative cancer appeared better in the Scottish cohort than in the original cohort. Calculated mean standardised Brier scores for PFS and OS were below 0.2 at all three follow-up points, suggesting good overall prognostic accuracy, but there was wide variation between predictive accuracy in individual patients. OroGrams shows prognostic accuracy at one-year follow up in Scotland. The accuracy decreases with longer follow-up periods.  相似文献   
37.
38.
39.
During 2008 to 2011, faecal samples, ear swabs, and ectoparasites obtained by full body search and total body comb were collected from 252 cats originating from the greater Tirana area. Faecal samples were examined using the McMaster and Baermann techniques, and a subset of 58 samples was tested for Giardia-specific antigen using a coproantigen enzyme-linked immunosorbent assay (ELISA). The ear swabs were examined for the presence of parasitic mites. Overall, almost 93 % of the cats were identified harbouring one or more parasites: 59.1 % (95 % confidence interval (CI), 53.0–65.0) and 86.9 % (95 % CI, 82.7–91.1) of the cats tested positive for ecto- or endoparasites, respectively; 53.2 % of the cats had evidence for concomitant ectoparasite infestation and endoparasite infection. For ectoparasite infestation, prevalence was 52.0 % for total fleas (Ctenocephalides felis, 51.2 %; Ctenocephalides canis, 2.0 %; and Leptopsylla segnis, 0.4 %), 8.3 % each for Felicola subrostratus and Otodectes cynotis and 4.0 % for Rhipicephalus sanguineus sensu lato. The most prevalent endoparasites were Toxocara ascarids (48.0 %), followed by Aelurostrongylus lungworms (39.7 %), Capillaria spp. (31.7 %), hookworms (32.9 %), dipylidiid cestodes (27.8 %), Cystoisospora spp. (23.4 %) and taeniid cestodes (2.0 %). One animal was found shedding Pseudamphistomum truncatum eggs. Giardia-specific antigen was detected in 29.3 % of the 58 cats tested. Mixed infections with up to six endoparasites concurrently (excluding Giardia) and mixed infestations with two or three species of ectoparasites were recorded in 73.1 and 22.8 % of the parasite-positive cats, respectively. Cats ≤9 months of age were more frequently tested (p?Toxocara and Cystoisospora infections than cats >9 months while these cats tested more often (p?Aelurostrongylus-positive compared with the younger cats. The prevalence of infestation with ectoparasites did not differ between the cats of these two age groups. Given the impact that some of the parasites may have upon animal health as well as the zoonotic potential of some of them, measures should be taken to minimise the transmission of these parasites.  相似文献   
40.
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