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   1271631篇
  免费   95584篇
  国内免费   1589篇
耳鼻咽喉   16386篇
儿科学   41238篇
妇产科学   35071篇
基础医学   190527篇
口腔科学   34959篇
临床医学   118692篇
内科学   249105篇
皮肤病学   27450篇
神经病学   102425篇
特种医学   47061篇
外国民族医学   265篇
外科学   179642篇
综合类   25948篇
现状与发展   3篇
一般理论   572篇
预防医学   105471篇
眼科学   28195篇
药学   93069篇
  7篇
中国医学   2035篇
肿瘤学   70683篇
  2018年   13652篇
  2017年   10481篇
  2016年   11426篇
  2015年   13206篇
  2014年   18151篇
  2013年   27773篇
  2012年   37940篇
  2011年   40347篇
  2010年   23275篇
  2009年   22444篇
  2008年   38075篇
  2007年   40775篇
  2006年   40314篇
  2005年   39424篇
  2004年   37884篇
  2003年   36266篇
  2002年   35166篇
  2001年   56230篇
  2000年   57268篇
  1999年   48298篇
  1998年   13495篇
  1997年   12313篇
  1996年   12718篇
  1995年   11987篇
  1994年   11170篇
  1993年   10478篇
  1992年   38369篇
  1991年   37821篇
  1990年   36593篇
  1989年   35400篇
  1988年   32798篇
  1987年   32161篇
  1986年   30658篇
  1985年   28930篇
  1984年   22037篇
  1983年   19298篇
  1982年   11447篇
  1981年   10389篇
  1979年   21055篇
  1978年   15468篇
  1977年   12866篇
  1976年   11920篇
  1975年   12875篇
  1974年   15655篇
  1973年   15434篇
  1972年   14584篇
  1971年   13627篇
  1970年   12843篇
  1969年   12116篇
  1968年   11266篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Borderline personality disorder is common in treatment settings and may be so in the general population. In this guide to assessment strategies for diagnosing borderline personality disorder, the authors discuss the reliability and validity of structured interviews and self-report instruments and suggest the use of a self-report questionnaire as a cost-effective screening test. Assessment problems, such as the need for longitudinal observation, are reviewed. Essential features of the recommended diagnostic approach include clarity about the diagnostic concept, consideration of the full range of diagnostic criteria, incorporation of recently developed diagnostic methodologies, care in distinguishing personality disorders from comorbid axis I syndromes, and complete assessment of the full range of axis II disorders.  相似文献   
993.
994.
Several investigators have suggested that microcomputers might serve as useful external aids for memory-impaired patients. However, knowledge of basic computer vocabulary may be necessary for patients to use and benefit from a microcomputer. The present paper describes a procedure, the method of vanishing cues, which facilitated the acquisition of computer-related vocabulary in four memory-impaired patients. The method involves the systematic reduction of letter fragments of to-be-learned words across trials. Although learning was slow and strongly dependent on first-letter cues, all patients acquired a substantial amount of the vocabulary and eventually were able to produce the target words in the absence of fragment cues. Further, they retained the vocabulary over a 6-week interval and showed some transfer of the knowledge they had acquired. These findings suggest that memory-impaired patients may eventually be able to use a microcomputer as a prosthetic device.  相似文献   
995.
After resection at birth of an accessory left foot, a white male infant was followed up for a slowly enlarging posterior calf mass of the same leg. When the patient was 8 years old, the mass was thought to have enlarged sufficiently to warrant excisional biopsy. Histologic examination of the tumor was consistent with the diagnosis of a dermoid cyst, revealing a lesion lined with stratified squamous epithelium and containing cutaneous adnexal structures represented by eccrine sweat glands. A congenital dermoid in the extremities is unusual. The prognosis following removal is good, and recurrence is rare.  相似文献   
996.
Fetal beta-endorphin release has been associated with fetal hypoxia. The purpose of this study was to assess the degree of uterine blood flow reduction needed to elicit fetal beta-endorphin release in the sheep since there is a large reserve of oxygen supply to the fetus. Uterine blood flow was reduced by 26 +/- 2, 46 +/- 3 and 66 +/- 2%, producing fetal oxygen content concentrations of 5.7 +/- 0.6, 4.4 +/- 0.7 and 2.6 +/- 0.3 ml/dl, respectively. Although fetal oxygen concentrations were significantly decreased in the groups with a reduction in uterine blood flow of 46 and 66%, beta-endorphin was elevated only in the latter group. It is speculated that fetal beta-endorphin is released at a level of hypoxia which leads to a decrease in fetal oxygen consumption. A reduction in uterine blood flow of 66% appears to produce a stressful environment for the fetus as measured by fetal plasma beta-endorphin levels.  相似文献   
997.
A randomized clinical trial was performed to compare the efficacy of bilateral oophorectomy with that of tamoxifen at a dose of 10 mg twice daily in premenopausal women with metastatic breast cancer, and to examine the efficacy of each as a crossover treatment. Initial treatment responses were seen in ten of 27 patients (37%) treated with oophorectomy and seven of 26 patients (27%) treated with tamoxifen. The difference was not statistically significant. Crossover responses were seen in five of 15 patients (33%) treated with oophorectomy, including three responses in ten prior tamoxifen nonresponders; and two of 18 patients (11%) treated with tamoxifen. Time to progression distributions were not significantly different during initial treatment, and no significant differences in survival were noted. Thus, there was no overall disadvantage to the use of tamoxifen as opposed to oophorectomy as initial hormonal therapy, and a failure to respond to tamoxifen did not preclude a response to subsequent oophorectomy. Exploratory data analysis within subsets indicated consistent differential treatment effects in the visceral dominant patients. Of the 16 such patients treated with oophorectomy, eight (50%) experienced objective responses but there were no responses in the 14 patients treated with tamoxifen. In the nine visceral dominant crossover patients who had not responded to initial tamoxifen, three (33%) subsequently responded to oophorectomy. Time to progression distributions within the visceral dominant subset appeared to be better for the patients treated initially with oophorectomy. However, one must be very cautious in drawing conclusions from exploratory subset analyses, especially with the small sample size. Further studies would be required to test any hypothesis of differential organ site responsiveness.  相似文献   
998.
Nurses must frequently make ethical decisions. These decisions require judgment, knowledge, and skills. This article will provide one framework for ethical decision making and provide several examples of the process.  相似文献   
999.
1000.
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