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   1075篇
  免费   132篇
  国内免费   9篇
耳鼻咽喉   11篇
儿科学   36篇
妇产科学   27篇
基础医学   132篇
口腔科学   42篇
临床医学   187篇
内科学   127篇
皮肤病学   18篇
神经病学   106篇
特种医学   72篇
外科学   112篇
综合类   23篇
预防医学   117篇
眼科学   89篇
药学   52篇
中国医学   11篇
肿瘤学   54篇
  2024年   3篇
  2023年   22篇
  2022年   38篇
  2021年   45篇
  2020年   61篇
  2019年   73篇
  2018年   70篇
  2017年   69篇
  2016年   53篇
  2015年   39篇
  2014年   69篇
  2013年   92篇
  2012年   63篇
  2011年   53篇
  2010年   50篇
  2009年   36篇
  2008年   58篇
  2007年   38篇
  2006年   34篇
  2005年   34篇
  2004年   28篇
  2003年   29篇
  2002年   20篇
  2001年   18篇
  2000年   15篇
  1999年   24篇
  1998年   5篇
  1997年   12篇
  1996年   3篇
  1995年   6篇
  1994年   8篇
  1993年   6篇
  1992年   11篇
  1991年   5篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   5篇
  1986年   3篇
  1985年   4篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
排序方式: 共有1216条查询结果,搜索用时 31 毫秒
1.
2.
中国新疆与哈萨克斯坦共和国生态环境特点极为相似,荒漠、半荒漠草地类型占草原面积的首位。由草原研究所派出的科技交流团,先后考察了哈国荒漠草地现状与改良利用情况,就优良旱生牧草新品种选育和荒漠、半荒漠区无灌溉条件下人工草地建植与管理技术模式达成技术合作事宜。  相似文献   
3.
OBJECTIVE: To prospectively determine the sonographic findings of nodular hyperplasia of the thyroid, to compare these with reported findings associated with malignancy, and to assess interobserver reliability. METHODS: Seventy thyroid nodules were scanned, and then biopsies of the nodules were performed under sonographic guidance with fine-needle cytologic analysis; in all cases images were reviewed by 2 experienced radiologists without knowledge of clinical outcome. Findings reported associated with malignancy were specifically assessed. Interobserver agreement between the expert and secondary readers for each finding was calculated by the kappa or weighted kappa statistic and the Fisher exact test of independence. RESULTS: There were 68 benign and 2 malignant nodules in a population of 63 female and 7 male patients. The mean benign nodule size was 2.9 cm; 60% were solid; 54% were hypoechoic; 59% were microlobulated or macrolobulated; 47% had central vascularity; 24% contained calcifications; and 82% were elliptical in shape. There was very good interobserver reliability for the presence of calcium (kappa = 0.91) and good agreement for the presence and location of vascularity (kappa = 0.75) and the amount of cystic components (kappa = 0.62; all P < .01). CONCLUSIONS: Sixty-nine percent of benign nodules had at least 1 finding reported previously as associated with malignancy. The interobserver reliability of the sonographic findings was good to very good for 3 of the 5 findings assessed.  相似文献   
4.
Since spontaneous reporting of adverse drug reactions depends on the physician's opinion of the relationship between the drug and the adverse event, we compared physicians' opinions with the scores obtained by the causality assessment method used in France. During a 2 month period, all physicians who reported adverse drug reactions (ADRs) to our pharmacovigilance centre expressed their opinions on the causal link by means of visual analogue scales. ADR reports were then assessed with the French causality assessment method by a clinical pharmacologist who was blind to physicians' opinions.The assessment by both physicians and the standardized method was performed for 75 ADR cases involving 120 drugs. Physicians used a wide range of assessments, with a preponderance of extreme scores, resulting in a U-shaped distribution, while the standardized method gave generally low scores. Scores given by physicians were very high (causality considered very likely or likely) in 60% of cases and very low (causality considered unlikely or dubious/possible) in 32% of cases. Scores obtained using the causality assessment method were low (causality dubious/possible) in 89% of cases and causality considered likely in only 11 cases, essentially in cases with positive rechallenge. Complete agreement occurred in only 6% of cases. Adding complete agreement and minor discrepancies raised the percentage to 49%.  相似文献   
5.
Non-genetic surrogacy characterizes a situation where the gestational mother is not the genetic mother. It further widens a circle that started with the introduction of in-vitro fertilization (IVF) and creates problems in defining motherhood and identifying at birth the mother who will have the rights and responsibilities of rearing the child.  相似文献   
6.
Objective. Tympanic temperature can be obtained instantaneously using an infrared emission detection (IRED) thermometer. Its accuracy has been documented in a variety of clinical settings, but its performance at low body temperatures is still unknown. In this study we evaluated its performance during coronary artery revascularization surgery in which mild hypothermic cardiopulmonary bypass (CPB) was used. Methods. Thirty adult patients undergoing coronary artery bypass graft surgery were enrolled in the study. Tympanic temperature obtained using IRED thermometry (Tt1) was compared with core temperatures from the esophagus (Te), and venous blood of CPB (Tv) before, during, and after CPB. We also measured tympanic temperature using a thermocouple probe (Tt2) in 16 of the 30 patients in order to study the agreement between the two methods. Values for correlation coefficients and limits of agreement were computed to assess the degree of agreement among the temperatures obtained. Results. The highest agreement with Tv during CPB was obtained from Tt1 (r = 0.94, 0.41 ± 1.73, limits of agreement) and from Te (0.91, 0.36 ± 2.46). Tt1 also showed good agreement with Tt2 during surgery. Conclusions. Infrared tympanic thermometry is a reliable, alternative method to measure tympanic temperature and may be useful to assess core temperature in both normothermic and mild hypothermic conditions.  相似文献   
7.
8.
Introduction - Interobserver variation among four observers in evaluation of eight selected neurological signs was investigated. Material & methods - Two hundred and two consecutive unselected inpatients were examined by two senior neurologists and two trainees, all without knowledge of the neurological case history. The signs examined were: anisocoria, jerky eye movements, facial palsy, elbow extension force, finger-nose test, Barré sign, knee jerk, and extensor plantar reflex. Observed agreement rates and kappa coefficients were calculated in order to compare the interobserver variability among neurologists and trainees, and to evaluate differences in the interobserver variability between signs. Results - Observed agreement rates varied from 0.80 to 0.95 for neurologists and from 0.65 to 0.98 for trainees. For neurologists kappa coefficients ranged from 0.40 to 0.67 and for trainees from 0.22 to 0.81. The neurologists had higher kappa values than the trainees in 5 signs, but this difference was only statistically significant for jerky eye movements. For the individual signs the observed agreement rates were between 0.50 and 0.93 for all four examiners combined, and overall kappa values varied from 0.32 to 0.71 with highest agreement for facial palsy and lowest for knee jerk. Conclusion - The magnitude of the interobserver and intersign variation indicates that the interpretation of the neurological signs tested, without knowledge of the case history, should be done with some caution.  相似文献   
9.
10.
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