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   5077篇
  免费   250篇
  国内免费   35篇
耳鼻咽喉   102篇
儿科学   173篇
妇产科学   140篇
基础医学   482篇
口腔科学   127篇
临床医学   422篇
内科学   1099篇
皮肤病学   122篇
神经病学   240篇
特种医学   308篇
外科学   880篇
综合类   143篇
一般理论   4篇
预防医学   336篇
眼科学   198篇
药学   321篇
中国医学   16篇
肿瘤学   249篇
  2023年   37篇
  2022年   82篇
  2021年   178篇
  2020年   84篇
  2019年   118篇
  2018年   138篇
  2017年   106篇
  2016年   143篇
  2015年   170篇
  2014年   196篇
  2013年   274篇
  2012年   334篇
  2011年   365篇
  2010年   202篇
  2009年   178篇
  2008年   308篇
  2007年   321篇
  2006年   313篇
  2005年   321篇
  2004年   255篇
  2003年   247篇
  2002年   197篇
  2001年   72篇
  2000年   76篇
  1999年   73篇
  1998年   37篇
  1997年   31篇
  1996年   26篇
  1995年   17篇
  1994年   14篇
  1993年   19篇
  1992年   28篇
  1991年   24篇
  1990年   26篇
  1989年   18篇
  1988年   25篇
  1987年   20篇
  1986年   30篇
  1985年   16篇
  1984年   18篇
  1983年   17篇
  1979年   13篇
  1978年   17篇
  1977年   9篇
  1975年   12篇
  1974年   20篇
  1973年   20篇
  1972年   16篇
  1971年   12篇
  1969年   9篇
排序方式: 共有5362条查询结果,搜索用时 78 毫秒
101.
The aim of this prospective experimental study was to evaluate the effect of light-emitting diode (LED) photobiomodulation therapy (LPT) on the stability of immediately loaded miniscrews under different force levels, as assessed by resonance frequency analysis (RFA). Sixty titanium orthodontic miniscrews with a length of 8 mm and a diameter of 1.4 mm were implanted into cortical bone by closed flap technique in each proximal tibia of 15 New Zealand white adult male rabbits (n = 30). The animals were randomly divided into irradiated and control groups under different force levels (0, 150, and 300 cN). OsseoPulse? LED device (Biolux Research Ltd.) 618 nm wavelength and 20 mW/cm(2) output power irradiation (20 minutes/day) was applied to the miniscrews for 10 days. The RFA records were performed at miniscrew insertion session (T1) and 21 days after surgery (T2). Wilcoxon and Mann-Whitney U-tests were used for statistical evaluation at P < 0.005 level. It was found that initial primer stability of all miniscrews was similar in all groups at the start of the experimental procedure. Statistically significant differences were found for changes in implant stability quotient (ISQ) values between LED-photobiomodulated group and the control (0 cN, P = 0.001; 150 cN, P < 0.001; and 300 cN, P < 0.001). Significant increase was found in ISQ values of LPT applied miniscrews under 0 cN (+11.63 ISQ), 150 cN (+10.50 ISQ), and 300 cN (+7.00 ISQ) force during observation period. By the increase of force levels, it was determined that ISQ values decreased in non-irradiated control miniscrews. Within the limits of this in vivo study, the present RFA findings suggest that LPT might have a favourable effect on healing and attachment of titanium orthodontic miniscrews.  相似文献   
102.
Inferior vena cava filters are commonly encountered devices on diagnostic imaging that were highlighted in a 2010 Food and Drug Administration safety advisory regarding their complications from long-term implantation. The Predicting the Safety and Effectiveness of Inferior Vena Cava Filters (PRESERVE) trial is an ongoing after-market study investigating the safety and utility of commonly utilized filters in practice today. While most of these filters are safe, prompt recognition and management of any filter-associated complication is imperative to prevent or reduce the morbidity and mortality associated with them. This review is aimed at discussing the appropriate utilization and placement of inferior vena cava filters in addition to the recognition of filter-associated complications on cross-sectional imaging. An overview of the PRESRVE trial filters is also provided to understand each filter's propensity for specific complications.  相似文献   
103.
International Journal of Mental Health and Addiction - This study aims to develop the Cyberostracism Scale (CS) to assess university students’ perceptions of virtual social exclusion....  相似文献   
104.
105.
Chloroquine is one of the antimalaria drugs, also used to treat rheumatoid arthritis and systemic lupus erythematosus (SLE). Although well tolerated in most individuals, it was suggested that chloroquine can exert a profound influence on renal function, especially in individuals with compromised body fluid status. However, epidemiological studies are still lacking. The renal actions of chloroquine are further exacerbated by co-administration of other commonly used drugs such as paracetamol. The following discussion will focus on the evidence that chloroquine is a stimulator of nitric oxide (NO), which mediates many of its renal actions (diuresis, natriuresis and an increase in both glomerular filtration rate (GFR) and plasma vasopressin). Chloroquine appears to modulate the renal tubular response to vasopressin either by directly inhibiting cAMP generation or indirectly via NO.  相似文献   
106.
BACKGROUND: Use of effective scolicidal agents during puncture, aspiration or injection of a scolicidal agent and reaspiration (PAIR) and surgery for hydatid cysts are essential to reduce the recurrence rate. In this in vitro study, we tried to determine the scolicidal property of a new agent, octenidine dihydrochloride, and of various agents in different concentrations and exposure times. MATERIAL AND METHODS: Echinococcus granulosus protoscoleces were obtained from six patients with liver (n=3) and lung (n=3) hydatid cysts. Various concentrations of octenidine dihydrochloride (0.1%, 0.01% and 0.001% diluted form), povidone iodine (10%, 1% and 0.1% diluted) and 20% saline were used in this study. Viability of protoscoleces was determined with dye-uptake (0.1% eosin) and flame cell activity. RESULTS: Octenidine dihydrochloride 0.1% had strong scolicidal effect in 15 min and octenidine dihydrochloride 0.01% in 30 min. Sixty percent of protoscoleces lost viability at 5 min with octenidine dihydrochloride 0.1%. Viability ratio decreased to 20% at 10 min, and all of them died at 15 min. Povidone iodine 10% and 1% had strong scolicidal effects after 15- and 30 min of exposure, respectively. Saline 20% killed all the protoscoleces in 30-min exposure. CONCLUSION: Because of the rapid and strong scolocidal effectiveness of octenidine dihydrochloride on protoscoleces, it may be used as a scolocidal agent during both perioperative and in the PAIR method.  相似文献   
107.
A 47‐year‐old male presented to our clinic with complaints of mass in both breasts. In the patient's history, he had undergone low anterior resection for rectum mucinous adenocarcinoma 2 years ago. The masses in both breasts of the patient were excised. Mucinous adenocarcinoma metastases were reported in the pathologic evaluation of the masses. Metastasis should be considered in patients with bilateral breast mass and previously diagnosed cancer even if the patient is male.  相似文献   
108.
Hellenic Journal of Surgery - Hepatolithiasis is the presence of stones within the intrahepatic bile ducts, regardless of common bile duct and gallbladder stones. It is rarely seen in our country...  相似文献   
109.
110.
BACKGROUND AND AIM: Abnormal myocardial acoustic properties have been reported in patients with idiopathic dilated cardiomyopathy (IDC). The aim of this study was to investigate the relationship between quantitative ultrasonic textural alterations of myocardium and clinical outcome in IDC. METHODS: Baseline clinical and echocardiographic variables were obtained from 28 patients with IDC. By using a videodensitometric approach, quantitative myocardial texture analysis was performed on images obtained from septum and posterior wall (PW). Cyclic variation (CV) index of mean gray level (MGL) was calculated according to the formula: (MGLdiast-MGLsyst)/MGLdiastx100. All patients were followed for an average of 11+/-5 months for the occurrence of cardiac death or repeated hospitalization due to worsening of heart failure. RESULTS: During follow-up, 10 patients experienced cardiac events (6 cardiac deaths and 4 heart failure events). The CV indexes of both septum and PW were significantly lower in patients with cardiac events than those of event free patients (6.8+/-9.6% vs. 13.6+/-8.2%, P<0.05 and 5.3+/-6.4% vs.15.7+/-7.2% P<0.001, respectively). Univariate analysis defined the following variables as predictors of outcome: PW-CV index (chi2=13.0, P=0.0003), transmitral E/A ratio (chi2=12.5, P=0.0004), symptom status (chi2=8.7, P=0.003), and septum-CV index (chi2=4.7, P=0.03). Multivariate stepwise regression analysis showed that the PW-CV index (chi2=7.5, P=0.006) and E/A ratio (chi2=6.5, P=0.01) were the independent predictors of outcome. The event-free survival rate of patients with PW-CV index <11% was significantly lower than those with an index > or = 11 (35.7% vs. 92.8%, P=0,001). CONCLUSION: The assessment of severely depressed CV index provides valuable prognostic information in patients with IDC.  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