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   3020篇
  免费   186篇
  国内免费   21篇
耳鼻咽喉   37篇
儿科学   90篇
妇产科学   72篇
基础医学   274篇
口腔科学   65篇
临床医学   295篇
内科学   621篇
皮肤病学   54篇
神经病学   132篇
特种医学   104篇
外科学   495篇
综合类   50篇
现状与发展   1篇
一般理论   8篇
预防医学   334篇
眼科学   113篇
药学   324篇
中国医学   26篇
肿瘤学   132篇
  2024年   6篇
  2023年   31篇
  2022年   93篇
  2021年   127篇
  2020年   96篇
  2019年   136篇
  2018年   155篇
  2017年   108篇
  2016年   118篇
  2015年   120篇
  2014年   152篇
  2013年   215篇
  2012年   267篇
  2011年   281篇
  2010年   144篇
  2009年   137篇
  2008年   185篇
  2007年   162篇
  2006年   150篇
  2005年   120篇
  2004年   94篇
  2003年   88篇
  2002年   59篇
  2001年   24篇
  2000年   14篇
  1999年   11篇
  1998年   12篇
  1997年   12篇
  1996年   9篇
  1995年   6篇
  1994年   6篇
  1993年   2篇
  1992年   8篇
  1991年   5篇
  1990年   7篇
  1989年   10篇
  1988年   2篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1980年   2篇
  1979年   8篇
  1978年   2篇
  1975年   6篇
  1974年   2篇
  1973年   4篇
  1972年   3篇
  1971年   3篇
  1963年   1篇
排序方式: 共有3227条查询结果,搜索用时 15 毫秒
71.
72.
73.

Objective

To investigate the relations between the vegetation cover and occurrence of cutaneous leishmaniasis (CL) in Golestan province during 2010-2012.

Methods

Data of monthly CL incidence and remote sensing normalized difference vegetation index (NDVI) of moderate resolution imaging spectroradiometer sensor were used in the study. Pearson''s correlation analysis was conducted to examine the type and strength of relationships between the spatially averaged NDVI variables (i.e. minimum, maximum and mean NDVI values) and CL incidence in township level. Spearman rank correlation was carried out to explain associations between the monthly CL incidence and NDVI variables at 0, 1, 2, 3 and 4 months lagged periods. Locations of CL cases at village level were geocoded and compared with frequency of CL cases in each NDVI-derived vegetation categories.

Results

Pearson''s analysis revealed significant associations between the NDVI variables and CL incidence at the township level (P<0.05). Results of Spearman analysis indicated that the highest correlations between NDVI variables and monthly CL incidence were established when the NDVI time-series lagged the CL incidence series NDVI variables. Purely spatial analysis demonstrated that despite majority of cases occurred at partially-vegetated areas, the possibility of CL occurrence was higher in bare soil areas by taking into account area of each vegetation zones.

Conclusions

lack or low vegetation cover is a major determinant of CL frequencies in Golestan province. The decrease of the mean vegetation density in townships is accompanied by increase of CL occurrence and vice versa.  相似文献   
74.
A green approach was developed for synthesizing a series of (isatin‐3‐ylidene)‐hydrazonamides 3a–j  from the reaction between isatin, (isatin‐3‐ylidene)malononitrile, or 2‐cyano‐2‐(2‐isatin‐3‐ylidene)acetate and benzohydrazonamide in ethyl acetate solutions at ambient temperature. The structures of the new compounds were confirmed on the basis of spectral data. In this eco‐friendly medium, a variety of (isatin‐3‐ylidene)hydrazonamides were obtained free of catalyst in good to excellent yields. All the synthesized products were evaluated for their antimicrobial activity. Among the compounds tested, 3b and 3d exhibited good antibacterial activity against Staphylococcus aureus, whereas others responded moderately with reference to the standard drug ciprofloxacin.  相似文献   
75.
The present meta-analysis evaluated the efficacy and safety of empagliflozin + linagliptin combination compared with either monotherapy [n=6 randomized controlled trials; 2857 adults with type 2 diabetes (T2DM) on diet + exercise ± metformin; 39.7% women; mean age: 54.6–59.9 years]. The combination of empagliflozin 10 mg + linagliptin 5 mg led to significantly greater reductions in glycated haemoglobin (HbA1c) compared with either drug alone over 24 weeks: weighted mean difference [WMD; −0.72%, 95% confidence interval (CI): −1.04, −0.40], and fasting plasma glucose (−1.60 mmol/L 95% CI: −2.21, −1.00). Similar results were observed when empagliflozin 25 mg + linagliptin 5 mg was compared with linagliptin 5 mg monotherapy or with empagliflozin 10 or 25 mg monotherapy. Patients with T2DM treated with the drug combination had more than three times higher likelihood of achieving HbA1c <7% than those on either monotherapy. Weight reduction was significantly greater in the combination group only when compared with linagliptin monotherapy. Safety profile was similar between combination treatment and monotherapies. Overall, the empagliflozin + linagliptin combination had superior efficacy and similar safety in achieving euglycaemia compared with either monotherapy. This combination, administered once daily, has the potential to reduce regimen complexity, enhance adherence and improve outcomes in clinical practice.  相似文献   
76.
77.
The establishment of drainage and the elimination of the origin of infection are essential procedures for successful management of odontogenic infections. Irrigation and aspiration are considered as the 2 main procedures for the treatment of facial space infections; we invented a new method named simultaneous irrigation and aspiration. The simultaneous irrigation and aspiration method is significantly less painful and less invasive compared with the standard surgical incision and drainage. This method was thought to be useful for managing facial infections if proper patient selection is performed.  相似文献   
78.
PurposeStudying the effect of surface roughness and thermal cycling on titanium–ceramic bonding.MethodsOne hundred fourteen samples in the form of bar for the C.P. titanium and Ti–6Al–4V alloy were used. They were divided into two groups according to the type of bar. Each group was then subdivided according to the type of surface treatment to three subgroups, control, airborne-particle abrasion and silica coated. Each subgroup was subdivided into two classes according to the type of test (surface roughness and bond strength). Samples used for the bond strength test were veneered. These samples were subdivided into two subclasses according to thermal cycling; whether without thermal cycling or after 6000 thermal cycles.ResultsThe surface roughness test results showed that silica coating recorded the highest surface roughness. Also C.P. titanium gave higher value of surface roughness than Ti–6Al–4V alloy. As regard the bond strength, the airborne-particle abrasion classes and the silica coated classes recorded bond strength values above the acceptable limit of 25 MPa determined in ISO 9693. As regard thermal cycling, the results showed that aging by thermal cycling decreased the metal–ceramic bond strength.ConclusionsThe airborne-particle abrasion and the silica coating are acceptable treatments for titanium–ceramic restorations. Increasing surface roughness of C.P. titanium and Ti–6Al–4V alloy not necessarily results in an increase in their bond strength to ceramics. Aging affects the metal–ceramic bond strength.  相似文献   
79.
Objectives: We studied the association between the prooxidant-antioxidant balance (PAB), anti-malondialdehyde-modified low-density lipoprotein (oxidized LDL, ox-LDL) IgG antibody and indices of cardiac function (systolic and diastolic function) in patients with coronary artery disease (CAD). Methods: Fifty-five patients with established CAD were selected, and serum levels of anti-ox-LDL IgG and PAB values were measured and compared with 40 matched healthy controls. Systolic and diastolic functions were determined for all patients. Results: PAB values were significantly higher in patients than in controls (p < 0.001), whilst serum anti-ox-LDL concentrations were not statistically different between the 2 groups (p = 0.821). However, after adjustment for high-density lipoprotein cholesterol, the patients had higher anti-ox-LDL levels (p = 0.04). Total PAB values were inversely associated with ejection fraction (r = -0.326, p = 0.031), but this was not the case for anti-ox-LDL in either group (p > 0.05). Conclusion: Serum concentrations of a marker of oxidative stress (PAB values) are inversely associated with cardiac function. PAB is a relatively simple index that could be incorporated into risk assessment in CAD patients. Anti-ox-LDL IgG antibody concentration does not appear to reflect total oxidative stress as assessed by PAB.  相似文献   
80.

Background

Prospective data on cardiac iron removal are limited beyond one year and longer-term studies are, therefore, important.

Design and Methods

Seventy-one patients in the EPIC cardiac substudy elected to continue into the 3rd year, allowing cardiac iron removal to be analyzed over three years.

Results

Mean deferasirox dose during year 3 was 33.6±9.8 mg/kg per day. Myocardial T2*, assessed by cardiovascular magnetic resonance, significantly increased from 12.0 ms ±39.1% at baseline to 17.1 ms ±62.0% at end of study (P<0.001), corresponding to a decrease in cardiac iron concentration (based on ad hoc analysis of T2*) from 2.43±1.2 mg Fe/g dry weight (dw) at baseline to 1.80 ±1.4 mg Fe/g dw at end of study (P<0.001). After three years, 68.1% of patients with baseline T2* 10 to <20 ms normalized (≥20 ms) and 50.0% of patients with baseline T2* >5 to <10 ms improved to 10 to <20 ms. There was no significant variation in left ventricular ejection fraction over the three years. No deaths occurred and the most common investigator-assessed drug-related adverse event in year 3 was increased serum creatinine (n=9, 12.7%).

Conclusions

Three years of deferasirox treatment along with a clinically manageable safety profile significantly reduced cardiac iron overload versus baseline and normalized T2* in 68.1% (32 of 47) of patients with T2* 10 to <20 ms.  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