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   26612篇
  免费   1423篇
  国内免费   76篇
耳鼻咽喉   410篇
儿科学   1132篇
妇产科学   873篇
基础医学   4275篇
口腔科学   607篇
临床医学   2181篇
内科学   5291篇
皮肤病学   538篇
神经病学   2580篇
特种医学   1171篇
外国民族医学   14篇
外科学   3790篇
综合类   126篇
一般理论   3篇
预防医学   1407篇
眼科学   503篇
药学   1383篇
中国医学   21篇
肿瘤学   1806篇
  2022年   213篇
  2021年   357篇
  2020年   236篇
  2019年   336篇
  2018年   421篇
  2017年   354篇
  2016年   495篇
  2015年   480篇
  2014年   647篇
  2013年   842篇
  2012年   1185篇
  2011年   1263篇
  2010年   644篇
  2009年   700篇
  2008年   1154篇
  2007年   1248篇
  2006年   1163篇
  2005年   1190篇
  2004年   995篇
  2003年   984篇
  2002年   908篇
  2001年   904篇
  2000年   936篇
  1999年   792篇
  1998年   372篇
  1997年   301篇
  1996年   245篇
  1995年   225篇
  1994年   204篇
  1993年   197篇
  1992年   485篇
  1991年   510篇
  1990年   494篇
  1989年   420篇
  1988年   400篇
  1987年   410篇
  1986年   406篇
  1985年   400篇
  1984年   276篇
  1983年   217篇
  1982年   150篇
  1981年   150篇
  1979年   261篇
  1978年   186篇
  1977年   155篇
  1976年   154篇
  1975年   170篇
  1974年   192篇
  1973年   167篇
  1972年   154篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
3.
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re…  相似文献   
4.
Ten years experience with acute peritoneal dialysis in 39 preterm-, newborn and small infants shows advantage and low risk of surgically implanted single dacron cuffed silicone catheters compared to trocar catheters.  相似文献   
5.
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue.  相似文献   
6.
7.
Angiotensin-converting enzyme (ACE) was studied immunohistochemically in conjunctival biopsies from 6 patients with systemic sarcoidosis, 4 patients with posterior non-sarcoid uveitis and in specimens from 4 patients with chalazion of the eyelid. Specimens with sarcoid granulomas showed intense ACE-positive immunoreactivity in epitheloid cells of the granuloma, whereas chalazion granulomas did not contain ACE-immunoreactivity. There was no difference in staining patterns between specimens without granulomas. Thus immunohistochemical staining for ACE may be of help in differentiating conjunctival granulomatous tissue of a chalazion from sarcoid granuloma.  相似文献   
8.
A case of testicular cancer in 2 brothers is reported and a review of the literature about testicular malignancies and etiologic factors in closely related family members is given. The familial incidence of testicular tumor is found to be 3% in twins and 0.6-2.1% in less closely related men. Tumors were of the same histology in 70-77% of the twins, whereas in brothers and in other degrees of relationship tumors of different histology mostly occur. Following the diagnosis of the tumor in the first man, the average interval to presentation of the tumor in the relative was 3.7 years in twins, 7.7 years in nontwin brothers and 13.5 years for less closely related men. The need for a thorough checkup of other family members is advised.  相似文献   
9.
Since the introduction of in vitro fertilization in 1978, reproductive medicine and its associated scientific fields have developed rapidly. In Germany, progress in this field is impeded by the German Embryo Protection Act. Exemplary are the prohibition of embryo selection and the ban on genetic testing of the pre-implantation embryo. Nevertheless, infertility treatment outcome has to be optimized within the framework of this law, with the aim of making treatment more efficient, lowering the incidence of multiple gestations, making ovarian hyperstimulation safer, as well as reducing the financial costs for the couple.  相似文献   
10.
Anemia has been associated with a poorer treatment response and reduced survival in women undergoing primary radiotherapy (RT) or radiochemotherapy for advanced cervical carcinoma. This study aimed to determine the influence of anemia on outcome in patients with cervical carcinoma undergoing adjuvant RT. Medical records were reviewed for 183 cervical cancer patients who had received adjuvant RT because of risk factors after radical surgery (n= 109) or inadequate primary surgery (simple hysterectomy; n= 74). Kaplan-Meier and Cox regression analyses were used to study hemoglobin levels before and during adjuvant RT in relation to recurrence-free and overall survival. Hemoglobin values > or =11 g/dL were considered normal, while those <11 g/dL indicated anemia. Hemoglobin levels before RT influenced significantly overall survival and recurrence-free survival across the whole group (overall survival--log rank(all patients)= 7.5; df = 1; P= 0.006). However, subgroup analysis showed that the observed difference was mainly due to the group of women who had undergone inadequate primary surgery (overall survival--log rank(inadequate surgery)= 10.8; df = 1; P= 0.001). Multifactorial regression analyses comparing hemoglobin before RT with grading and tumor stage confirmed the prognostic value of hemoglobin values. Maintaining normal hemoglobin values before and during adjuvant RT seems to be important, especially in patients who have had inappropriate simple hysterectomy, which may resemble a therapeutic situation.  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