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   387031篇
  免费   24765篇
  国内免费   7997篇
耳鼻咽喉   4270篇
儿科学   10642篇
妇产科学   7517篇
基础医学   31056篇
口腔科学   8962篇
临床医学   42690篇
内科学   49474篇
皮肤病学   5093篇
神经病学   20971篇
特种医学   8777篇
外国民族医学   312篇
外科学   40984篇
综合类   58024篇
现状与发展   12篇
一般理论   30篇
预防医学   40071篇
眼科学   5521篇
药学   36225篇
  401篇
中国医学   33729篇
肿瘤学   15032篇
  2023年   5877篇
  2022年   9516篇
  2021年   14644篇
  2020年   13497篇
  2019年   20049篇
  2018年   17649篇
  2017年   14065篇
  2016年   11163篇
  2015年   10466篇
  2014年   24959篇
  2013年   25345篇
  2012年   21507篇
  2011年   22954篇
  2010年   19960篇
  2009年   18180篇
  2008年   16141篇
  2007年   15651篇
  2006年   13611篇
  2005年   11701篇
  2004年   9501篇
  2003年   8305篇
  2002年   6531篇
  2001年   5809篇
  2000年   4813篇
  1999年   4167篇
  1998年   3385篇
  1997年   3232篇
  1996年   2801篇
  1995年   2680篇
  1994年   2594篇
  1993年   2065篇
  1992年   2093篇
  1991年   1806篇
  1990年   1587篇
  1989年   1427篇
  1988年   1337篇
  1987年   1156篇
  1985年   4605篇
  1984年   5970篇
  1983年   4450篇
  1982年   4586篇
  1981年   4380篇
  1980年   3837篇
  1979年   3537篇
  1978年   3097篇
  1977年   2231篇
  1976年   2687篇
  1975年   2095篇
  1974年   1830篇
  1973年   1667篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Glycine is unique among the amino acids in view of its symmetric nature. While the overall distribution of glycyl residues in the (φ, ø) plane is near-symmetric, there can be certain preferences for the individual conformations. An analysis of the observed glycyl conformations in 70 proteins has been carried out to find the influence of residues adjoining the glycyl residues. For this purpose, the (φ, ø) plane has been divided into two regions: (a) the region in which φ is negative and (b) the region in which φ is positive. The analysis is done in terms of the number of conformations occurring in these regions. It has been found that while the overall percentage distribution of glycyl residues between the positive and the negative φ regions is 54:46, the distribution shows asymmetry when the examples are sorted out in terms of X-Gly and Gly-Y doublets. The asymmetry becomes more prominent when the data are sorted out into triplets X-Gly-Y. Using the available information, it has been possible to designate 25 triplets as P-predominant and 19 as N-predominant. An examination of P-predominant triplets for possible occurrence in β-bends having one of the conformations in the positive φ region shows that only 25% are of this nature. Thus, the P-preference of P-predominant triplets is not an outcome of the bend formation alone and must be an inherent property of these triplets.  相似文献   
952.
本文报告乳腺积乳囊肿43例。讨论了发病原因及病理,特别提出局部肿块波动感试验阳性,A超检查显示液平段,试穿抽出乳汁,对诊断有肯定价值;治疗以手术切除为主,仅有7例穿刺抽吸乳汁得以治愈。  相似文献   
953.
Zusammenfassung Über ein Jahr wurden 1082 allgemeinchirurgische Planeingriffe prospektiv konsekutiv erfaßt und ihre Komplikationen mit einem Score bewertet. EinflußgröBen und die Komplikationsraten, die unter Umständen von der Kliniks-organisation abhängig sind, sollten analysiert werden. Es fand sich eine Beziehung zwischen Komplikationen und Wochentag, Operationsdauer sowie der Abweichung der tatsächlich benötigten von der geplanten Operationszeit. Mit höherer Auslastung der Operationssäle pro Arbeitstag stiegen die Komplikationsraten ebenfalls an.Keinen Einfluß auf die Komplikationsraten hatten Operationsbeginn und-monat sowie die monatliche Auslastung der Säle. Ob das Wetter einen Einfluß auf die Komplikationsraten nahm, konnte nicht entschieden werden: so fanden sich im Sommer- höhere Komplikationsraten als im Winterhalbjahr, jedoch war der Score von der Höhe der Außentemperatur und der Luftfeuchtigkeit unabhängig.
The influence of time of operation and hospital organization on postoperative complication rates
Summary During a 1-year period 1082 general surgical interventions were prospectively documented and their complication rates evaluated by a score system. Factors responsible for the complication rates and possibly depending on hospital organization should be analysed. The complication rates were influenced by the selection of the weekday, the length of operation time and the extent of discrepancy between planned and required operation time. Furthermore, the complication rates paralleled the extent of utilization of the operation theatre during a workday. The complication rates werenot affected by the beginning of operation and the operation month as well as the monthly utilization of the operation theatres. Whether the weather did influence the complication rates could not be decided: higher complication rates were found in the summer as compared to the winter period, but the complication score was independent of the level of the outside temperature and humidity.
  相似文献   
954.
用秩和比法对我院的10个公示病种医疗质量进行综合评价   总被引:2,自引:0,他引:2  
宁葵 《中国医院统计》2007,14(4):315-317
目的对我院2005年度公示的10个病种进行医疗质量综合评价。方法采用秩和比法(RSR)进行统计分析。结果我院的10个公示病种被划分成4个医疗质量等级:老年性白内障、小儿支气管肺炎2个病种质量为优,急性阑尾炎、腹股沟疝(单侧)、子宫平滑肌瘤、剖宫产4个病种质量为良,胃大切、脑梗塞、急性心肌梗塞3个病种质量为中,脑出血1个病种质量为差。结论通过对综合指数秩和比(RSR)的计算并根据其值分级归档,反映出所研究病种之间存在着医疗质量高低的差异。控制和降低本院临床常见病种的医药费用,进行医疗全程连续性控制,为患者提供经济有效的医疗服务。  相似文献   
955.
M. Turgut 《Acta neurochirurgica》2007,149(10):1063-1069
Summary   Background. Şerefeddin Sabuncuoğlu (A.D. 1385–1468) was the author of the first illustrated surgery atlas Cerrahiyyetü’l Haniyye (Imperial Surgery), which was written in Turkish in 1465. The purpose of this report is to present his unique contribution to modern neurological surgery. Methods. Cerrahiyyetü’l Haniyye consists of 412 pages in three chapters, in which there are a total of 191 sections dealing with a variety of surgical specialties, including neurosurgery. In each section of the book, a sentence written in rhyme and meter gives the diagnosis, classification and surgical technique in detail. Şerefeddin Sabuncuoğlu describes medical and surgical management of neurological diseases such as spinal trauma, epilepsy, migraine, facial palsy, hemiplegia, low back pain, cranial fracture, hydrocephalus and abscesses of the head in his textbook. Conclusions. Şerefeddin Sabuncuoğlu was a great surgeon in Turkish medical history and the sections on neurological diseases in Cerrahiyyetü’l Haniyye are of great importance in neurosurgery. Today, he is justified as a pioneer of surgery, an investigator and a medical illustrator in the early period of Ottoman Empire. His atlas is a modification of original contributions from earlier treatises.  相似文献   
956.
优选前后精子顶体酶活性与IVF受精率相关性的研究   总被引:1,自引:0,他引:1  
目的探讨优选处理前和处理后精子顶体酶活性的变化,及与体外受精(IVF)受精率的相关性。方法采用分光光度比色法,对接受IVF治疗的53例不育夫妇男方精液,分别测定优选处理前和处理后精子顶体酶活性,分析其与IVF受精率的相关性。结果优选处理后精子顶体酶活性与优选前比较有显著性差异(P<0.05);达到常规IVF标准并选择常规IVF治疗者,优选后的精子顶体酶活性与IVF受精率有相关性,精子顶体酶活性降低与IVF受精率降低有关。结论精子顶体酶活性与IVF受精率有相关性,并且通过精子顶体酶活性可以预测IVF受精率。  相似文献   
957.
958.
959.
This article, based on a report prepared for the International Council of Ophthalmology (ICO) and the International Society for Low Vision Research and Rehabilitation (ISLRR), explores the assessment of various aspects of visual functioning as needed to document the outcomes of vision rehabilitation. Documenting patient abilities and functional vision (how the person functions) is distinct from the measurement of visual functions (how the eye functions) and also from the assessment of quality of life. All three areas are important, but their assessment should not be mixed. Observation of task performance offers the most objective measure of functional vision, but it is time‐consuming and not feasible for many tasks. Where possible, timing and error rates provide an easy score. Patient response questionnaires provide an alternative. They may save time and can cover a wider area, but the responses are subjective and proper scoring presents problems. Simple Likert scoring still predominates but Rasch analysis, needed to provide better result scales, is gaining ground. Selection of questions is another problem. If the range of difficulties does not match the range of patient abilities, and if the difficulties are not distributed evenly, the results are not optimal. This may be an argument to use different outcome questions for different conditions. Generic questionnaires are appropriate for the assessment of generic quality of life, but not for specific rehabilitation outcomes. Different questionnaires are also needed for screening, intake and outcomes. Intake questions must be relevant to actual needs to allow prioritization of rehabilitation goals; the activity inventory presents a prototype. Outcome questions should be targeted at predefined rehabilitation goals. The Appendix cites some promising examples. The Low Vision Intervention Trial (LOVIT) is an example of a properly designed randomized control study, and has demonstrated the remarkable effectiveness of vision rehabilitation. It is hoped that further similar studies will follow.  相似文献   
960.
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