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   2159篇
  免费   106篇
  国内免费   40篇
耳鼻咽喉   15篇
儿科学   166篇
妇产科学   40篇
基础医学   205篇
口腔科学   136篇
临床医学   138篇
内科学   536篇
皮肤病学   24篇
神经病学   80篇
特种医学   163篇
外科学   199篇
综合类   128篇
预防医学   95篇
眼科学   116篇
药学   143篇
中国医学   6篇
肿瘤学   115篇
  2022年   23篇
  2021年   70篇
  2020年   35篇
  2019年   39篇
  2018年   49篇
  2017年   31篇
  2016年   50篇
  2015年   59篇
  2014年   64篇
  2013年   85篇
  2012年   124篇
  2011年   84篇
  2010年   85篇
  2009年   72篇
  2008年   99篇
  2007年   103篇
  2006年   76篇
  2005年   67篇
  2004年   70篇
  2003年   56篇
  2002年   54篇
  2001年   57篇
  2000年   39篇
  1999年   45篇
  1998年   45篇
  1997年   41篇
  1996年   32篇
  1995年   25篇
  1994年   19篇
  1993年   22篇
  1992年   23篇
  1991年   20篇
  1990年   25篇
  1989年   39篇
  1988年   45篇
  1987年   44篇
  1986年   38篇
  1985年   54篇
  1984年   25篇
  1983年   18篇
  1979年   23篇
  1978年   15篇
  1977年   13篇
  1976年   15篇
  1975年   15篇
  1974年   21篇
  1971年   19篇
  1970年   22篇
  1969年   14篇
  1968年   15篇
排序方式: 共有2305条查询结果,搜索用时 15 毫秒
71.
During routine dissection of 82-year-old female cadaver with no known unfavorable medical history, we observed bilateral bifid ureter and variation in arterial supply of left kidney only. Careful examination revealed that there were bifid ureters on both sides enclosed in single facial sheath. It was also observed that both the ureter have different pattern of origin. On the right side, both the ureters were seen to be emerging from the hilum, one below another and joined together at the brim of the lesser pelvis just before crossing the right external iliac artery. Right kidney was supplied by single renal artery lying anterior to both the ureters. On the left side one ureter emerged from the hilum while the second one exited the kidney from a prominent lobule present below the inferior pole.  相似文献   
72.
73.
74.

Background

Traditional periodontal open flap debridement (OFD) results in reduced pocket depth (PD), clinical attachment loss (CAL), gingival recession (GR) and postoperative pain and discomfort. The quest to overcome these shortcomings has led to research into Er,Cr:YSGG laser assisted pocket therapy (ELAPT). This study was designed to compare the clinical outcomes of ELAPT versus OFD.

Methods

Fifteen patients with a PD of ≥5 mm and ≤8 mm at two sites were selected. Test sites (Group 1) were treated by ELAPT and the control (Group 2) by OFD. Clinical parameters were recorded at baseline, 3 and 6 months and included Plaque Index (PI), Gingival Index (GI), modified Sulcular Bleeding Index (mSBI), PD, CAL and GR.

Results

Both treatments produced a reduction in PI, GI, mSBI and PD, an increase in GR, and a gain in CAL at 3 and 6 months. The mean gain of CAL in Group 1 at 3 and 6 months (1.60 ± 0.78 and 1.80 ± 0.63) was similar (p > 0.05) to the value of Group 2 (1.93 ± 0.88 and 2.00 ± 0.54). GR increased significantly (p < 0.05) only in Group 2 at 3 and 6 months (1.80 ± 0.56 and 1.87 ± 0.64) compared to Group 1 (0.50 ± 0.68 and 0.60 ± 0.74).

Conclusions

ELAPT compared with OFD results in similar CAL gains with less GR and significant reductions in PD, GI and mSBI, and may be considered as an alternative to surgical therapy.  相似文献   
75.

Purpose

Acute myocardial infarction (AMI) drives an intense inflammatory response that contributes to infarct healing and cardiac remodeling. Recently, different studies have identified a role of interleukin-1 (IL-1) in the development of adverse cardiac remodeling. However, in animal models of AMI IL-1 has been shown to be cardioprotective in preconditioning, raising the question of clinical safety of therapeutic IL-1 blockade for autoinflammatory diseases or for the prevention or the treatment of AMI. In this study we proposed to evaluate the effects of pretreatment with recombinant human interleukin-1 receptor antagonist (rhIL-1Ra) on ischemia reperfusion (I/R) injury to the heart.

Methods

RhIL-1Ra was given 4?h or 30?min before the surgical induction of I/R. Left ventricular ejection fraction(LVEF) and infarct size were assessed to determine the effects of the drug pretreatment compared to vehicle treated mice.

Results

RhIL-1Ra, given 4?h or 30?min before the onset of the ischemia, showed marked cardioprotection though preservation of the LVEF (no change vs sham operated mice) and the reduction of the infarct size (?40?% vs vehicle-treated mice). No differences were observed between the two groups of rhIL-1Ra treatment.

Conclusions

IL-1 blockade therapies using rhIL-1Ra prior the onset of AMI protects the myocardium and preserves cardiac function.  相似文献   
76.
77.
The peripheral retina is affected in a variety of retinal disorders. Traditional fundus cameras capture only a part of the fundus even when montaging techniques are used. Ultra-wide field imaging enables us to delve into the retinal periphery in greater detail. It not only facilitates assessing color images of the fundus, but also fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and red and green free images. In this review, a literature search using the keywords “ultra-widefield imaging”, “widefield imaging”, and “peripheral retinal imaging” in English and non-English languages was done and the relevant articles were included. Ultra-wide field imaging has made new observations in the normal population as well as in eyes with retinal disorders including vascular diseases, degenerative diseases, uveitis, age-related macular degeneration, retinal and choroidal tumors and hereditary retinal dystrophies. This review aims to describe the utility of ultra-wide field imaging in various retinal disorders.  相似文献   
78.
Background. There is sparse literature on the association of adipose tissue with liver histology in patients with nonalcoholic fatty liver disease (NAFLD).Aim. To study the correlation of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and total adipose tissue (TAT) with liver histology in Indian patients with NAFLD.Material and methods. A single slice CT scan at the level of L4-L5 vertebrae was done to assess the abdominal VAT and SAT volumes in 21 patients with histological diagnosis of NAFLD. Adult treatment panel III criteria with modified abnormal waist were used to define metabolic syndrome (MS). Histological grading was done according to the NAFLD activity score (NAS).Results. Twenty-one patients with NAFLD [13 males, median age: 35 years, median BMI: 25.97 kg/m2] were included prospectively. Even though overweight/obese patients had severe liver disease, there was no difference in the volume of VAT adjusted for BMI between 6 (28.5%) lean and 15 (71.5%) overweight/obese patients. Patients with NASH and borderline NASH were older, obese with higher VAT and SAT volumes than no-NASH group. SAT volume (SATV) correlated significantly with hepatic steatosis but none of the adipose tissue volumes had any correlation with other histological variables. Both SATV and TAT volume (TATV) correlated significantly with severity of liver disease as determined by NAS score whereas presence of MS or insulin resistance had no correlation with histological severity.Conclusion. Both subcutaneous and total adipose tissue volume are related to the disease severity as determined by NAFLD activity score in Indian patients with NAFLD.  相似文献   
79.
Polycrystalline samples of Ba0.96Ca0.04Ti0.91Fe0.09O3 were prepared using a conventional solid state reaction route with different Fe starting precursors (Fe2O3, Fe3O4). The Rietveld refined XRD data confirmed the phase purity and tetragonal crystal structure of both the samples. The average grain size measured using SEM was ≈0.40 μm in both the samples. XPS analysis confirmed the presence of only Fe2+ and both Fe2+/Fe3+ in Fe2O3 and Fe3O4 doped BCT samples. The Pr and Mr values have been measured to be 1.34 μC cm−2, 2.88 μC cm−2 and 0.0015 emu g−1 and 0.135 emu g−1 in Fe2O3 and Fe3O4 doped BCT samples, respectively. The Fe3O4 doped samples exhibit much better M-E coupling (≈22%) as compared to Fe2O3 (≈7%) doped BCT samples. The results obtained hence suggest that Fe3O4 doping in BCT is better suited for multiferroic applications.

Polycrystalline samples of Ba0.96Ca0.04Ti0.91Fe0.09O3 were prepared using a conventional solid state reaction route with different Fe starting precursors (Fe2O3, Fe3O4). A significant difference in the magnetic and ferroelectric properties was observed.  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