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   1502677篇
  免费   115116篇
  国内免费   3028篇
耳鼻咽喉   21453篇
儿科学   46295篇
妇产科学   40844篇
基础医学   225045篇
口腔科学   43901篇
临床医学   134186篇
内科学   284493篇
皮肤病学   31744篇
神经病学   114467篇
特种医学   58419篇
外国民族医学   242篇
外科学   230312篇
综合类   37949篇
现状与发展   3篇
一般理论   415篇
预防医学   114435篇
眼科学   35662篇
药学   114193篇
  3篇
中国医学   3784篇
肿瘤学   82976篇
  2018年   14553篇
  2016年   12772篇
  2015年   14611篇
  2014年   20449篇
  2013年   30902篇
  2012年   41363篇
  2011年   43484篇
  2010年   25572篇
  2009年   24019篇
  2008年   40869篇
  2007年   44451篇
  2006年   44553篇
  2005年   42906篇
  2004年   42066篇
  2003年   40290篇
  2002年   38949篇
  2001年   67898篇
  2000年   69344篇
  1999年   57963篇
  1998年   16430篇
  1997年   14574篇
  1996年   14711篇
  1995年   13941篇
  1994年   13173篇
  1992年   47339篇
  1991年   46680篇
  1990年   45721篇
  1989年   44681篇
  1988年   41306篇
  1987年   40305篇
  1986年   38408篇
  1985年   36792篇
  1984年   27876篇
  1983年   23774篇
  1982年   14223篇
  1981年   12918篇
  1980年   12261篇
  1979年   27156篇
  1978年   19471篇
  1977年   16469篇
  1976年   15420篇
  1975年   16832篇
  1974年   20458篇
  1973年   19560篇
  1972年   18546篇
  1971年   17251篇
  1970年   16507篇
  1969年   15717篇
  1968年   14285篇
  1967年   13059篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
72.
73.
74.
75.
76.
Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.

Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.

Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).

Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC50 value of 13.8?mg/mL on PLA2 from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC50 value of 16.6?mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC50 value of 0.92?mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of??128.96 compared to standard phenidone (?103.61). Thus, the current study validates the application of WS for inflammatory diseases.

Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.  相似文献   
77.
78.
79.
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma  相似文献   
80.
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