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   64017篇
  免费   4676篇
  国内免费   186篇
耳鼻咽喉   825篇
儿科学   1767篇
妇产科学   1600篇
基础医学   10510篇
口腔科学   1698篇
临床医学   6064篇
内科学   12878篇
皮肤病学   968篇
神经病学   5972篇
特种医学   2816篇
外国民族医学   45篇
外科学   8251篇
综合类   549篇
一般理论   83篇
预防医学   4960篇
眼科学   1207篇
药学   4648篇
中国医学   163篇
肿瘤学   3875篇
  2022年   386篇
  2021年   1031篇
  2020年   653篇
  2019年   923篇
  2018年   1137篇
  2017年   789篇
  2016年   920篇
  2015年   1094篇
  2014年   1351篇
  2013年   2332篇
  2012年   3001篇
  2011年   3097篇
  2010年   2243篇
  2009年   1891篇
  2008年   2796篇
  2007年   2965篇
  2006年   2933篇
  2005年   2774篇
  2004年   2830篇
  2003年   2577篇
  2002年   2648篇
  2001年   2166篇
  2000年   2216篇
  1999年   1994篇
  1998年   924篇
  1997年   773篇
  1996年   678篇
  1995年   694篇
  1994年   576篇
  1993年   636篇
  1992年   1455篇
  1991年   1409篇
  1990年   1345篇
  1989年   1347篇
  1988年   1119篇
  1987年   1124篇
  1986年   1058篇
  1985年   980篇
  1984年   710篇
  1983年   667篇
  1982年   475篇
  1981年   456篇
  1980年   396篇
  1979年   626篇
  1978年   383篇
  1977年   365篇
  1975年   377篇
  1974年   414篇
  1973年   348篇
  1972年   340篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
162.
Edited by Lauren Dundes. Walnut Creek (CA): Altamira Press, 2003. 239 pages. $27.95, paperback, $75.00, hardback.  相似文献   
163.
PURPOSE: To investigate whether a single pre-operative dose of 120 mg acetylsalicylic acid (ASA) decreased either (1) emboli rate, as detected by transcranial Doppler (TCD), during and early after carotid endarterectomy (CEA) and (2) clinical intra- and post-operative signs suggestive of embolism or increased bleeding tendency. DESIGN: Prospective, double-blind placebo controlled trial. PATIENTS AND METHODS: One-hundred consecutive patients were randomised to receive either 120 mg ASA (n = 48) or placebo (n = 49) by suppository on the night before CEA; three patients were excluded. Emboli were counted and expressed as emboli rate (ER). The incidence of bleeding complications was assessed. Surgeons were asked to indicate which patients had received ASA or placebo. RESULTS: There were no significant differences between the ASA and placebo groups in ER in the intraoperative and postoperative periods. ER higher than 0.9 min(-1) was associated with a significantly increased risk of complications (26 vs. 0%, P < 0.01). No extra bleeding complications were observed in the ASA group. Surgeon assessment of whether or not ASA had been administered had a sensitivity of 42% and a specificity of 70%. CONCLUSION: A single pre-operative dose of ASA (120 mg) did not reduce significantly the emboli rate during and after CEA and surgeons could not correctly identify whether or not ASA had been administered.  相似文献   
164.
In genetic epidemiological studies informative families are often oversampled to increase the power of a study. For a proband‐family design, where relatives of probands are sampled, we derive the score statistic to test for clustering of binary and quantitative traits within families due to genetic factors. The derived score statistic is robust to ascertainment scheme. We considered correlation due to unspecified genetic effects and/or due to sharing alleles identical by descent (IBD) at observed marker locations in a candidate region. A simulation study was carried out to study the distribution of the statistic under the null hypothesis in small data‐sets. To illustrate the score statistic, data from 33 families with type 2 diabetes mellitus (DM2) were analyzed. In addition to the binary outcome DM2 we also analyzed the quantitative outcome, body mass index (BMI). For both traits familial aggregation was highly significant. For DM2, also including IBD sharing at marker D3S3681 as a cause of correlation gave an even more significant result, which suggests the presence of a trait gene linked to this marker. We conclude that for the proband‐family design the score statistic is a powerful and robust tool for detecting clustering of outcomes.  相似文献   
165.
166.
167.
This study was undertaken to evaluate changes in relative (99m)Tc-hydrazinonicotinamide (HYNIC)-annexin V tumor uptake over time in patients undergoing chemotherapeutic treatment at baseline and at 5-7 h and 40-44 h after treatment initiation. Imaging results are related to clinical outcomes, as assessed with response evaluation criteria in solid tumors (RECIST). METHODS: We prospectively included 20 patients (11 men and 9 women; mean age, 59.8 y; range, 22-75 y) scheduled for chemotherapy (n = 19) or bisphosphonate treatment (n = 1). Curable disease was present in 5 patients. The other patients had metastatic disease and were treated in a palliative setting. Three of the 20 enrolled patients were excluded from analysis: 1 patient ultimately refused the proposed chemotherapy treatment; because of difficulties with the labeling procedure, 1 patient did not receive a pretreatment scan; and 1 patient presented with an allergic reaction (rash and nausea) to the (99m)Tc-HYNIC-annexin V formulation. The remaining 17 patients underwent 3 scintigraphic scans with (99m)Tc-HYNIC-annexin V: before treatment and 5-7 h and 40-44 h after treatment initiation. The tumor response was evaluated with RECIST and related to observed changes in the ratios of tumor activity to background activity for the largest known lesion; values exceeding 25% the baseline value on either the 5- to 7-h scan or the 40- to 44-h scan were considered significant. RESULTS: With the proposed sequential imaging protocol and a 25% change threshold, responders to treatment could be separated from nonresponders with a 94% accuracy (16/17 patients). CONCLUSION: Sequential (99m)Tc-HYNIC-annexin V imaging may allow for assessment of the response to chemotherapy within 3 d after treatment initiation.  相似文献   
168.
Background. Medication adherence impacts healthcare utilization. Pharmacy records are useful to establish fill patterns. Objective. Use pharmacy records to establish medication patterns fill patterns for comparison to healthcare utilization. Methods. Pharmacy records of 175 children with persistent asthma were collected and compared to healthcare utilization. Results. Majority of subjects had significant healthcare utilization, low numbers of rescue medications, and poor controller medication fill rates. Those with more rescue medications had more healthcare utilization and more controller medications. Conclusions. Pharmacy fill patterns demonstrate few rescue and/or controller medication fills. Those with more rescue medications reported increased healthcare utilization despite controller medications.  相似文献   
169.
170.
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