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   27792篇
  免费   1718篇
  国内免费   71篇
耳鼻咽喉   243篇
儿科学   617篇
妇产科学   498篇
基础医学   3901篇
口腔科学   648篇
临床医学   2573篇
内科学   5306篇
皮肤病学   474篇
神经病学   3084篇
特种医学   1125篇
外国民族医学   55篇
外科学   3835篇
综合类   359篇
一般理论   10篇
预防医学   2173篇
眼科学   784篇
药学   1920篇
中国医学   32篇
肿瘤学   1944篇
  2022年   194篇
  2021年   384篇
  2020年   231篇
  2019年   380篇
  2018年   432篇
  2017年   358篇
  2016年   396篇
  2015年   540篇
  2014年   719篇
  2013年   1067篇
  2012年   1575篇
  2011年   1634篇
  2010年   894篇
  2009年   837篇
  2008年   1543篇
  2007年   1653篇
  2006年   1586篇
  2005年   1603篇
  2004年   1529篇
  2003年   1432篇
  2002年   1401篇
  2001年   399篇
  2000年   346篇
  1999年   355篇
  1998年   310篇
  1997年   302篇
  1996年   258篇
  1995年   245篇
  1994年   212篇
  1993年   210篇
  1992年   219篇
  1991年   201篇
  1990年   182篇
  1989年   193篇
  1988年   193篇
  1987年   191篇
  1986年   170篇
  1985年   174篇
  1984年   222篇
  1983年   190篇
  1982年   228篇
  1981年   209篇
  1980年   192篇
  1979年   167篇
  1978年   153篇
  1977年   106篇
  1976年   142篇
  1975年   126篇
  1974年   151篇
  1973年   113篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).

Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.

Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).

Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).

Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.

Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED.  相似文献   
2.
Cultures of performativity may contribute to organizational and individual arrogance. Workplace organizations have individuals who at various times will display arrogance, which may manifest in behaviours, such as an exaggerated sense of self-importance, dismissiveness of others, condescending behaviors and an impatient manner. Arrogance is not a flattering label and irrespective of the reason or the position of power, in the context of organizational behaviors, may not be useful and may even be detrimental to the work environment. Thus, it is timely to reflect on the implications of arrogance in the workplace. Advocacy and empowerment can be undermined and relationships adversely impacted, including the achievement of positive consumer outcomes. This paper provides an introduction to arrogance, and then discusses arrogance to promote awareness of the potential consequences of arrogance and its constituent behaviors.  相似文献   
3.
4.
5.
Agenesis of the Gallbladder Revisited Laparoscopically   总被引:1,自引:0,他引:1  
Gallbladder agenesis is an extremely rare disease. Necropsy incidence has been reported to be 0.016%. Failure lo locate the gallbladder at the time of a planned cholecystectomy can be very challenging. We report such a case during a laparoscopic cholecystectomy. The indication for surgery in these patients are complaints of gallbladder symptoms along with a false-positive ultrasound study. During exploration, an abnormal location of the gallbladder has to be excluded. Ectopic gallbladder locations include intrahepatic, lesser omentum, retroperitoneal, retrohepatic, within the falciform ligament, retroduodenal, and retrohepatic areas. Thorough exploration and cholangiography are essential. Embryologically, the gallbladder and cystic duct arise from the caudal portion of the hepatic bud. All of the previously reported cases of gallbladder agenesis have shown an absence of both the gallbladder and cystic duct. We report an embryological oddity wherein a patent cystic duct was found along with an agenetic gallbladder. This is the first case report of this finding, along with this being the first absent gallbladder discovered laparoscopically.  相似文献   
6.
A series of 5-hydroxy and 5-benzyloxy analogs of the antiarrhythmic and multidrug resistance (MDR) modulating drug propafenone was synthesized and the MDR-modulating activity of the compounds was evaluated using a daunomycin efflux assay system. The key step of the synthesis is the selective reduction of the double bond in 1 without cleavage of the benzyl group thus leading to the phenol 3 . Alkylation with epichlorohydrine followed by nucleophilic epoxide ring opening gave the benzylated target compounds 5a–d . Subsequent cleavage of the benzyl group gave the 5-hydroxy analogs 6a–d . Structure activity relationship studies showed, that the 5-hydroxy derivates 6a–d fit the log P/log potency correlation line previously established for a series of propafenone analogs. In contrast, all four 5-benzyloxy analogs 5a–d showed almost identical EC50 values, independent of their log P value.  相似文献   
7.
Inborn errors of the urea cycle are an important cause of hyperammonaemia throughout childhood, and are associated with high morbidity and mortality rates. If they are diagnosed early and treated appropriately, the outcome for affected children is significantly improved.  相似文献   
8.
9.
Microvascular thrombosis is a prominent feature in cardiac delayed xenograft rejection (DXR). We investigated the impact of warfarin or low-molecular-weight heparin (LMWH) anti-coagulation on xenograft function using a heterotopic pig-to-primate model. Donor hearts were from CD46 transgenic pigs and baboon immunosuppression included tacrolimus, sirolimus, anti-CD20 and TPC, an alpha-galactosyl-polyethylene glycol conjugate. Three groups of animals were studied. Group 1 (n = 9) was treated with warfarin, Group 2 (n = 13) with LMWH and Group 3, received no anti-coagulant drugs. The median duration of xenograft function was 20 days (range 3-62 days), 18 days (range 5-109 days) and 15 days (range 4-53 days) in Groups 1 to 3 respectively. Anti-coagulation achieved the targeted international normalized prothrombin ratio (INR) and anti-factor Xa levels consistent with effective in vivo therapy yet, no significant impact on median xenograft function was observed. At rejection, a similar histology of thrombosis and ischemia was apparent in each group and the levels of fibrin deposition and platelet thrombi in rejected tissue was the same. Anti-coagulation with warfarin or LMWH did not have a significant impact on the onset of DXR and microvascular thrombosis. However, a role for specific anti-coagulant strategies to achieve long-term xenograft function cannot be excluded.  相似文献   
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