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   4595篇
  免费   258篇
  国内免费   14篇
耳鼻咽喉   50篇
儿科学   220篇
妇产科学   95篇
基础医学   594篇
口腔科学   83篇
临床医学   276篇
内科学   685篇
皮肤病学   122篇
神经病学   305篇
特种医学   140篇
外科学   569篇
综合类   100篇
一般理论   1篇
预防医学   270篇
眼科学   249篇
药学   519篇
中国医学   51篇
肿瘤学   538篇
  2023年   33篇
  2022年   77篇
  2021年   145篇
  2020年   78篇
  2019年   111篇
  2018年   145篇
  2017年   102篇
  2016年   133篇
  2015年   123篇
  2014年   153篇
  2013年   229篇
  2012年   358篇
  2011年   360篇
  2010年   215篇
  2009年   169篇
  2008年   255篇
  2007年   241篇
  2006年   224篇
  2005年   215篇
  2004年   180篇
  2003年   149篇
  2002年   125篇
  2001年   63篇
  2000年   74篇
  1999年   65篇
  1998年   33篇
  1997年   25篇
  1996年   26篇
  1995年   24篇
  1994年   23篇
  1993年   20篇
  1992年   53篇
  1991年   50篇
  1990年   45篇
  1989年   64篇
  1988年   48篇
  1987年   48篇
  1986年   36篇
  1985年   33篇
  1984年   31篇
  1983年   29篇
  1982年   16篇
  1981年   16篇
  1979年   35篇
  1978年   15篇
  1976年   16篇
  1974年   14篇
  1973年   20篇
  1972年   15篇
  1970年   15篇
排序方式: 共有4867条查询结果,搜索用时 15 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.
3.
4.
Abstract

Background: The prognostic nutritional index (PNI), a marker of immune-nutrition balance, has predictive value in the survival and prognosis of various cancers. However, the impact of PNI on response to chemoradiation is poorly understood.

Materials and Methods: A total of 583 women with locally advanced cervical cancer from two centers were clinically assessed for complete response after chemoradiation. The baseline PNI was individually recorded, and the significance of association between PNI and complete response was analyzed using logistic regression. ROC (receiver operating characteristics) curves were analyzed to determine the cutoff value of PNI that significantly predicted complete response.

Results: Logistic regression analysis demonstrated that the PNI was significantly associated with complete response following chemo radiation (p?<?0.0001). Analysis of the ROC curve for PNI demonstrated an optimal cut off value of 44.8 (p?<?0.0001, sensitivity 66.7, and specificity 88.5); the area under the ROC curve was 0.813 (Youden’s index J, 0.7519).

Conclusions: The PNI is significantly associated with clinical complete response to chemoradiation in locally advanced cervical cancer. Low baseline PNI may lower the likelihood of complete response after chemoradiation. In particular, those with PNI values below 44 should be carefully monitored during treatment; nutritional interventions may offer benefit in these women.  相似文献   
5.
The abdominal compartment syndrome is a life threatening condition resulting from pathologic elevation of the intraabdominal pressure. Prompt diagnosis is required to avoid significant sequelae. Diagnosis of this syndrome is based on clinical findings and intra abdominal pressure monitoring. Treatment consists of decompressive laparotomy, which corrects the pathology. Various surgical techniques are described to manage the open abdomen. Despite considerable attention accorded to this disorder, it is still associated with high morbidity and mortality. This review article deals with the identification of risk factors, pathophysiology, diagnostic criteria and treatment of critically ill patients with the abdominal compartment syndrome.  相似文献   
6.
Carcinoma gallbladder is the commonest malignancy in the Northern part of India. The heavy metals are known carcinogens while trace metals have protective effect. Aim The aim of the study is to estimate the heavy and trace metal (Lead, Zinc, Copper, Cadmium, Chromium, Manganese and Selenium) concentration in serum, bile, tissue and gallstone in patients with gallbladder diseases. Method This is a pilot study conducted in 45 cases (Group – I: 15 cases of carcinoma gallbladder, Group II: 15 patients of cholecystitis with cholelithiasis and Group – III: 15 patients of healthy control), to detect the relationship between the heavy and trace metal concentration and gall bladder carcinoma. Analysis of metal was done using Perkins‐Elmer model 2380 atomic absorption spectrophotometer. Results The serum concentration of copper and nickel was significantly high in carcinoma gallbladder patients as compared to patients with cholecystitis while zinc and selenium is low in carcinoma gallbladder patients. Bile concentration of zinc, selenium and manganese was significantly low in carcinoma gallbladder patients (p < 0.05) as compared to patients of cholelithiasis while cadmium and nickel was high. Tissue concentration of manganese was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis while chromium was high. Gallstone concentration of copper, manganese and lead was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis. Conclusion The heavy metals are in higher concentration in carcinoma gallbladder while trace metals are in lower concentration indicating possible role of heavy metal in gallbladder carcinogenesis.  相似文献   
7.
8.
BACKGROUND: The periodontal ligament (PDL) is a soft tissue interposed between the tooth and the alveolar bone. It is responsible for transmission of forces in vivo; this promotes bone remodeling. The purpose our study was to use fractal analysis to quantify the complex morphology of the PDL-bone interface. METHODS: We used Scion Image (Scion Corp, Frederick, Md) and Benoit fractal analysis (Tru Soft International, St. Petersburg, Fla) programs to calculate the fractal dimension of the PDL-bone interface in rats via the box-counting method. Rats in the experimental groups received an initial force of 0.1N or 0.5N with customized springs for 6 hours. RESULTS: Our studies showed an increase in normal fractal dimension at the root apices of the rats' maxillary molars. We also found evidence that the fractal dimension varies along the entire root length from the apex to the cementoenamel junction. CONCLUSIONS: Mechanical loading might lead to an increase in fractal dimension at the PDL-bone interface apart from mechanisms of bone cell directed remodeling. These changes in fractal dimension are proportional to loading and could provide a new parameter for force determination in orthodontic tooth movement.  相似文献   
9.
Growing rats were exposed to 5 mg/L Pb,ad libitum in drinking water, and administered low or high doses of Mn and Cd intraperitoneal (i.p.) for 30 days. Some groups of animals were also administered combinations of Pb + Mn and Pb + Cd in an identical manner. Analysis of Pb, Mn, and Cd in tissue samples showed the expected dose-dependent accumulation when the metal was administered singly. However, combined treatment produced different types of metal shift in different tissues. Enhanced accumulation of all three metals in the brain, Mn in liver, Pb in kidney and Cd in testis and kidney after combined exposure may make target organs vulnerable to the toxic effects of metals, even when encountered at low concentrations. Further, the decreased levels of blood Pb after combined treatment with Cd or Mn suggests that the significance of blood Pb level as a diagnostic aid for Pb toxicity in coexposed conditions may not be of much value. Changes in the metallic distribution within the tissues after coexposure may be the result of a competition between the administered metals for common binding sites.  相似文献   
10.
目的探讨肝、肺细胞因子基因表达与腹腔吞噬细胞上清液、循环血中细胞因子含量的关系,为临床诊治多细菌感染引发的炎症提供实验依据.方法将30只小鼠分为假手术对照组(sham组)和盲肠结扎组(CLP组).采用RT-PCR法检测肝脏和肺脏肿瘤坏死因子α(TNF-α)和白细胞介素10(IL-10)的基因表达情况,采用ELISA法检测腹腔巨噬细胞上清液和循环血液中相应细胞因子含量.结果CLP组的TNF-α、IL-10基因表达和腹腔巨噬细胞上清液、循环血液中的相应细胞因子含量均高于sham组.CLP后18h组与4h组比较,TNF-α在腹腔巨噬细胞上清液、循环血液中的活性均有显著性差异(P<0.05),在肝、肺中基因表达有非常显著性差异(P<0.01);IL-10在腹腔巨噬细胞上清液和循环血液中的含量无显著性差异,而在肝、肺中基因表达有显著性差异.结论发生多细菌感染性炎症时,肝、肺参与细胞因子的表达;血液中细胞因子含量不能完全代表组织器官内的基因表达情况;多细菌感染性炎症治疗应考虑靶器官细胞因子的表达状态.  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