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   3119篇
  免费   164篇
  国内免费   3篇
耳鼻咽喉   47篇
儿科学   125篇
妇产科学   49篇
基础医学   337篇
口腔科学   53篇
临床医学   187篇
内科学   522篇
皮肤病学   57篇
神经病学   222篇
特种医学   116篇
外科学   385篇
综合类   91篇
预防医学   224篇
眼科学   245篇
药学   359篇
中国医学   13篇
肿瘤学   254篇
  2023年   17篇
  2022年   57篇
  2021年   70篇
  2020年   32篇
  2019年   57篇
  2018年   59篇
  2017年   49篇
  2016年   70篇
  2015年   67篇
  2014年   82篇
  2013年   123篇
  2012年   229篇
  2011年   213篇
  2010年   106篇
  2009年   96篇
  2008年   138篇
  2007年   149篇
  2006年   143篇
  2005年   135篇
  2004年   128篇
  2003年   113篇
  2002年   102篇
  2001年   67篇
  2000年   75篇
  1999年   80篇
  1998年   35篇
  1997年   19篇
  1996年   22篇
  1995年   17篇
  1993年   18篇
  1992年   67篇
  1991年   57篇
  1990年   56篇
  1989年   52篇
  1988年   27篇
  1987年   38篇
  1986年   38篇
  1985年   33篇
  1984年   31篇
  1983年   31篇
  1981年   14篇
  1980年   17篇
  1979年   24篇
  1978年   21篇
  1976年   14篇
  1974年   20篇
  1973年   35篇
  1972年   14篇
  1971年   15篇
  1970年   18篇
排序方式: 共有3286条查询结果,搜索用时 15 毫秒
11.
Morphometric analyses of liver parenchymal cells were performed on male albino rats fed a semipurified diet supplemented with two levels of copper and zinc. These metals were administered in demineralized drinking water to four groups of animals at two levels. (1) 0.25 μgm Cu/ml, 2.5 μgm Zn/ml, and (2) 1.0 μgm Cu/ml, 10 μgm Zn/ml. Cadmium, also administered in the drinking water daily to rats at 17.2 μgm cadmium/ml, was given to one group of animals on each of the two semipurified diets. Two groups of rats were given laboratory chow plus 17.2 μgm Cd/ml for 71 days and for 280 days. Volume densities of all organelles diminished significantly when levels of copper and zinc were lowest. Surface densities of rough and smooth endoplasmic reticulum were significantly decreased. Higher levels of copper and zinc produced morphologic and morphometric parameters which fell just below those obtained for rats fed chow. Glycogen accumulation was highest when the levels of metal were low. Lipid inclusions were more frequent with semipurified diets than with chow. Hepatocytes from rats fed the semipurified diet with low copper and zinc plus cadmium demonstrated a significant increase in smooth endoplasmic reticulum compared to animals fed the semipurified diet alone. The smooth endoplasmic reticulum changed little when cadmium was given to rats receiving adequate copper and zinc. Smooth endoplasmic reticulum increased when diets included chow and cadmium whereas rough endoplasmic reticulum decreased. Cup-shaped and elongated mitochondria with longitudinal cristae appeared in hepatocytes from animals fed chow with cadmium. These were not seen with semipurified diets and cadmium.  相似文献   
12.
13.
14.
15.
16.
Acute transverse myelitis: MR characteristics   总被引:4,自引:0,他引:4  
Magnetic resonance imaging findings in 13 patients with acute transverse myelitis are reviewed. In 12 cases centrally located high intensity signal extending over few spinal segments was noted. The lesion occupied more than two thirds of the cord's cross-sectional area in 8 patients. Central dot sign was noted in 7 patients. Variable cord enlargement was seen in 5 patients. Contrast study in one patient showed peripheral enhancement. The MR characteristics that help in differentiating transverse myelitis from spinal form of multiple sclerosis are discussed.  相似文献   
17.
We report three patients with pyomyositis due to Staphylococcus aureus. Magnetic resonance imaging aided in the accurate diagnosis of the infection and of the extent of involvement. Incision, drainage and antibiotic therapy eradicated the infection in all the patients. We suggest clinical or subclinical bacteraemic seeding of the diseased muscle, as the most likely mechanism for pyomyositis.  相似文献   
18.
19.
Circadian administration of chemotherapy has been reported to decrease toxicity and possibly enhance efficacy. Between March 1991 and December 1993, 18 evaluable patients with progressive, hormone-refractory metastatic prostate cancer were treated in this phase II trial of circadian infusion floxuridine (FUDR). The drug was delivered through a central venous catheter using a CADD-Plus computerized pump such that approximately 70% of the drug was administered between 3 and 9 p.m. and the rest (30%) was administered between 9 p.m. and 3 p.m. The dose of FUDR was 0.15 mg/kg/day × 14 days every 4 weeks. A total of 79 complete cycles was administered.Two of 18 evaluable patients (11.1%) had decreases in PSA lasting five and eight months. No objective responses or improvement in bone scans was noted. The major toxicity observed was diarrhea. Although circadian infusion FUDR is feasible and tolerable, it has limited activity in hormone refractory prostate cancer.  相似文献   
20.
Benign lesions of glottis creates stiffness of the vocal fold and inefficient glottal valve, aerodynamically effecting the vocal quality by preventing smooth vocal edge closure. Introduction of phonomicrosurgical techniques based on Hirano ’s principle of vocal fold epithelium have revolutionized results of voice surgery. Our experience in the management of benign vocal fold lesions by phonomicrosurgical techniques with pre and post operative stroboscopic, perceptual and computerized acoustic voice analysis is described.  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