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   929篇
  免费   84篇
  国内免费   45篇
耳鼻咽喉   2篇
儿科学   92篇
妇产科学   19篇
基础医学   99篇
口腔科学   19篇
临床医学   148篇
内科学   271篇
皮肤病学   8篇
神经病学   46篇
特种医学   135篇
外科学   44篇
综合类   27篇
预防医学   40篇
眼科学   7篇
药学   63篇
中国医学   1篇
肿瘤学   37篇
  2023年   4篇
  2022年   8篇
  2021年   4篇
  2020年   6篇
  2019年   12篇
  2018年   20篇
  2017年   7篇
  2016年   14篇
  2015年   18篇
  2014年   29篇
  2013年   33篇
  2012年   25篇
  2011年   24篇
  2010年   36篇
  2009年   34篇
  2008年   31篇
  2007年   50篇
  2006年   23篇
  2005年   23篇
  2004年   26篇
  2003年   31篇
  2002年   24篇
  2001年   18篇
  2000年   26篇
  1999年   29篇
  1998年   53篇
  1997年   38篇
  1996年   43篇
  1995年   29篇
  1994年   19篇
  1993年   25篇
  1992年   17篇
  1991年   17篇
  1990年   24篇
  1989年   38篇
  1988年   40篇
  1987年   27篇
  1986年   27篇
  1985年   20篇
  1984年   14篇
  1983年   11篇
  1982年   9篇
  1981年   7篇
  1980年   8篇
  1979年   3篇
  1978年   8篇
  1977年   12篇
  1976年   5篇
  1975年   6篇
  1967年   2篇
排序方式: 共有1058条查询结果,搜索用时 15 毫秒
1.
2.
3.
A variation in the bioactivity of different production lots of human menopausal gonadotropin (hMG) has been suggested. Therefore, we evaluated ovarian response to hMG in 14 women during three separate IVF cycles. The first two cycles were performed with the same lot (#03310027; Cycles A1 and A2); the third cycle utilized different lots of hMG (Cycle B). In all cycles, hMG was administered 3 ampules/day beginning cycle Day 3 and continued for at least 6 days. Estradiol and ultrasound evaluations were performed on Day 3, and then daily, beginning on cycle Day 8. Fourteen women completed all three cycles. There were no significant differences in baseline estradiol and ultrasound. Estradiol levels on Day 8 (A1, 754 +/- 130; A2, 700 +/- 107; B, 520 +/- 80 pg/ml, analysis of variance p greater than 0.5) and on Day 9 (A1, 1051 +/- 144; A2, 1140 +/- 155; B, 840 +/- 124 pg/ml, p greater than 0.05) were similar as well. The number of small (1.0-1.4 cm) follicles, large (greater than or equal to 1.5 cm) follicles, and total follicles (Day 8: total A1, 5.5 +/- 0.9; A2, 4.0 +/- 0.7; B, 4.5 +/- 0.9, p greater than 0.05; Day 9: total A1, 6.7 +/- 0.9; A2, 6.9 +/- 0.8; B, 6.9 +/- 0.9, p greater than 0.05) in all three cycles were also similar.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
4.
5.
6.
Sperm quality in Hodgkin's disease versus non-Hodgkin's lymphoma   总被引:3,自引:4,他引:3  
The study was conducted to determine the deleterious effect of lymphoma disease on spermatogenesis and to evaluate the possibility that the disease is mediated primarily by inherent mechanisms in Hodgkin's disease and non-Hodgkin's lymphoma patients. A total of 89 patients with lymphoma disease (Hodgkin's and non-Hodgkin's) were referred for sperm preservation prior to adjuvant treatments. A comparison was made of pre- and post-thaw sperm quality between lymphoma patients and healthy volunteers who applied for sperm donation. This was followed by further assessment of the differences between patients with Hodgkin's disease and non-Hodgkin's lymphoma in terms of sperm variables, clinical parameters and blood hormone concentrations. It was found that patients with lymphoma disease had significantly impaired pre-freeze and post-thaw sperm quality compared with that of healthy volunteers. Patients with non-Hodgkin's lymphoma had spermatozoa of higher quality than patients with Hodgkin's disease. No differences were found in the clinical or hormonal parameters between these two groups. As expected, reduced testicular size and abnormal testicular consistency were correlated with decreased sperm quality. The mere presence of cancer disease has a direct negative effect on spermatogenesis, which is probably not related to incidental side-effects. A variable degree of impairment should be expected with different categories of cancer.   相似文献   
7.
OBJECTIVE: To assess the relationship between impaired glucose tolerance and both vascular dementia and AD. BACKGROUND: Diabetes and abnormalities of glucose metabolism have been associated with stroke and poor cognitive function. In addition, glycoproteins and glycosylation have been postulated to be associated with the development of neuritic plaques characteristic of AD. METHODS: A historical prospective cohort study of Japanese-American men (n = 3,774), who were examined at ages 45 to 68 (1965 through 1968) and again at ages 71 to 93 (1991 through 1993). Measurements were obtained by clinical and home examinations: assessment of glucose intolerance (nonfasting 1 hour after glucose load) from 1965 through 1968 and history of diabetes diagnosed by a physician at examinations given from 1965 through 1968 and from 1976 through 1978. At the 1991 through 1993 examinations, the Cognitive Assessment Screening Instrument (CASI)-an instrument designed for use in cross-cultural settings combining features of the Folstein Mini-Mental State Examination, the Modified Mini-Mental State Examination, and the Hasegawa Dementia Screening Scale-was used. Diagnosis and classification of AD and vascular dementia were made by a consensus panel using neuropsychologic assessment data, a neurologist's evaluation, and information from a family informant. Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised criteria were used to establish dementia, and subclassification by cause was based on other published criteria. RESULTS: No association between AD and diabetes, present either 25 or 15 years previously, was found after adjustment for age and education in a multiple regression model. A significant association was found between impaired glucose tolerance at baseline and vascular dementia (p < 0.01). CONCLUSIONS: These findings confirm expected relationships between impaired glucose tolerance and stroke-related dementia but do not support an association of disordered glucose metabolism with AD.  相似文献   
8.
9.
10.
BACKGROUND: The goal of this study was to assess variations with age in the management of breast carcinoma and to identify determinants of care received. METHODS: A stratified random sample was selected among women age > or = 50 newly diagnosed with lymph node negative breast carcinoma in Quebec in 1988, 1991, and 1993. Information was abstracted from medical charts. Predictors of definitive locoregional treatment (total mastectomy with lymph node dissection or breast-conserving surgery with both axillary lymph node dissection and radiation therapy) were identified by multiple logistic regression analysis. RESULTS: Overall, 1174 patients age > or = 50 years with breast carcinoma were included. Women age > or = 70 years were much less likely to receive definitive locoregional treatment compared with women ages 50-69 years (48.7% vs. 83.5%; P < 0.0001). Older women were less likely to undergo surgery with breast preservation (76.7% vs. 86.3%; P < 0.0001), radiation therapy (54.7% vs. 90.5%; P < 0.0001), dissection of the axillary lymph nodes (55.6% vs. 86.3%; P < 0.0001), or chemotherapy (1.2% vs. 13.9%; P < 0.0001), but not treatment with tamoxifen (66.4% vs. 64.7%; P = 0.41). Adjusting for comorbidity and other characteristics related to the disease, the hospital, and the attending physician, age remained a strong determinant of the probability of receiving definitive locoregional treatment (odds ratio [OR], 0.14; 95% confidence interval [95% CI], 0.12-0.18 for women age > or = 70 years vs. women ages 50-69 years). The same association was observed when women who did not undergo lymph node dissection but who received systemic adjuvant treatment were considered to have received definitive therapy (OR, 0.13; 95% CI, 0.10-0.17) for women age > or = 70 years vs. women ages 50-69 years). CONCLUSIONS: Less aggressive patterns of care are provided to elderly breast carcinoma patients, independent of comorbidity. This could explain, at least in part, the sustained breast carcinoma mortality in this population.  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