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   2542篇
  免费   168篇
  国内免费   30篇
耳鼻咽喉   14篇
儿科学   124篇
妇产科学   33篇
基础医学   428篇
口腔科学   23篇
临床医学   189篇
内科学   454篇
皮肤病学   52篇
神经病学   115篇
特种医学   240篇
外科学   129篇
综合类   167篇
预防医学   243篇
眼科学   62篇
药学   251篇
中国医学   19篇
肿瘤学   197篇
  2023年   23篇
  2022年   30篇
  2021年   88篇
  2020年   39篇
  2019年   55篇
  2018年   53篇
  2017年   47篇
  2016年   58篇
  2015年   65篇
  2014年   93篇
  2013年   117篇
  2012年   143篇
  2011年   152篇
  2010年   106篇
  2009年   83篇
  2008年   135篇
  2007年   107篇
  2006年   112篇
  2005年   77篇
  2004年   86篇
  2003年   93篇
  2002年   67篇
  2001年   61篇
  2000年   58篇
  1999年   58篇
  1998年   58篇
  1997年   41篇
  1996年   38篇
  1995年   36篇
  1994年   29篇
  1993年   33篇
  1992年   35篇
  1991年   44篇
  1990年   44篇
  1989年   38篇
  1988年   33篇
  1987年   44篇
  1986年   35篇
  1985年   29篇
  1984年   25篇
  1983年   16篇
  1982年   16篇
  1981年   14篇
  1980年   22篇
  1979年   23篇
  1978年   10篇
  1977年   11篇
  1976年   10篇
  1975年   6篇
  1969年   5篇
排序方式: 共有2740条查询结果,搜索用时 15 毫秒
1.
For the separate development of radioimmunoassay procedures for thioridazine and its two major active metabolites, mesoridazine and sulforidazine, three haptens, respectively, 2-methylthio-, 2-methylsulfinyl-, and 2-methylsulfonyl-substituted 10-[2-[l-(2-carboxyethyl)-2-piperidinyl]ethyl]-10H-phenothiazine, were synthesized and characterized. Thioridazine hapten was coupled to bovine serum albumin, whereas the haptens for mesoridazine and sulforidazine were coupled to porcine thyroglobulin. The number of hapten residues per mole of carrier protein was determined in each case by an ultraviolet spectrophotometric method. Polyclonal antibodies to each hapten–protein conjugate were obtained in rabbits, and titers of the antisera were checked by evaluating their binding characteristics to the appropriate tritiated analyte. A hapten for the ring sulfoxide metabolite of thioridazine was also synthesized.  相似文献   
2.
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class.  相似文献   
3.
4.
5.
Fourteen patients of non-cirrhotic portal fibrosis (NCPF) with portal hypertension were put on oral diltiazem hydrochloride (90 mg/day) or placebo on a prospective, randomised, single blind basis for 15 days. Predrug hemodynamic and biochemical status were similar in both groups. Diltiazem produced significant reduction (p less than 0.001) in mean intrasplenic pressure: from 41.88 (SD +/- 6.18) to 21.5 (+/- 7.91) cm of normal saline as against 45.56 (+/- 9.45) to 43.33 (+/- 8.27) in the placebo group. Mean arterial pressure (MAP), heart rate and cardiac output (CO) did not change in either group. Thus, the calcium channel blocker diltiazem reduces portal pressure in patients with NCPF, independent of reduction in MAP and CO; this is advantageous in situations where compromised cardiac hemodynamics may prove deleterious.  相似文献   
6.
7.
38 cases of sarcoma of head and neck region were analysed in a retrospective way in relation to age, anatomic location, histological, clinical profile, and surgical approaches. Compared to other types of head and neck neoplasms, such as squamous cell carcinoma, soft tissue sarcomas have low rates of regional metastases. However the biological behaviour of soft tissue sarcoma is more aggressive specially in paediatric age group. In the present series, CT scan was considered as the primary modality of investigation. Surgery generally has been recommended as the primary method of treatment for achieving local control, except in those high-grade tumours arising in sites not amenable to resection. 3-year and 5-year survival rates in this present series 50% and 31.6% respectively.  相似文献   
8.
9.
10.
A 14-year-old male presented with abdominal pain, diarrhoea and a sensation of something prolapsing through the anus during defecation, and was found to have diffuse colonic polyposis. There was no evidence of mucocutaneous hyperpigmentation and family history was negative, suggesting a diagnosis of non-familial juvenile polyposis. Histological analysis of multiple endoscopic biopsies showed features typical of juvenile or retention type (hamartomatous) lesions: dilated cystic glands lined by mucocus-secreting epithelium and prominent, inflamed and congested lamina propria. However, admixed with these features, focal areas of atypical adenomatous changes were recognized. Even the intervening normal-looking colonic mucosa showed some dysplastic changes. These findings indicate that hamartomatous and atypical adenomatous epithelial changes can co exist in non-familial juvenile polyposis and the latter may confer a risk of malignant transformation in this otherwise non-neoplastic disease.  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