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   59580篇
  免费   4160篇
  国内免费   1984篇
耳鼻咽喉   483篇
儿科学   1286篇
妇产科学   2267篇
基础医学   7173篇
口腔科学   1249篇
临床医学   4974篇
内科学   6212篇
皮肤病学   844篇
神经病学   4341篇
特种医学   1664篇
外国民族医学   7篇
外科学   4522篇
综合类   8874篇
现状与发展   3篇
一般理论   6篇
预防医学   5321篇
眼科学   1712篇
药学   7237篇
  69篇
中国医学   4677篇
肿瘤学   2803篇
  2024年   169篇
  2023年   845篇
  2022年   1478篇
  2021年   2095篇
  2020年   1929篇
  2019年   1894篇
  2018年   1825篇
  2017年   1819篇
  2016年   1803篇
  2015年   1724篇
  2014年   3266篇
  2013年   4197篇
  2012年   3283篇
  2011年   3713篇
  2010年   2992篇
  2009年   2686篇
  2008年   2671篇
  2007年   2711篇
  2006年   2432篇
  2005年   2233篇
  2004年   1918篇
  2003年   1889篇
  2002年   1457篇
  2001年   1372篇
  2000年   1166篇
  1999年   1127篇
  1998年   984篇
  1997年   955篇
  1996年   864篇
  1995年   851篇
  1994年   707篇
  1993年   601篇
  1992年   538篇
  1991年   488篇
  1990年   493篇
  1989年   419篇
  1988年   302篇
  1987年   266篇
  1986年   322篇
  1985年   435篇
  1984年   416篇
  1983年   255篇
  1982年   332篇
  1981年   267篇
  1980年   288篇
  1979年   211篇
  1978年   176篇
  1977年   166篇
  1976年   154篇
  1975年   111篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
辽宁产东亚钳蝎毒镇痛作用与脑内中枢关系的研究   总被引:3,自引:0,他引:3  
应用立体定位、核团内注射与电解损毁核团技术及微电极细胞外记录方法,以猫丘脑后核内脏大神经诱发单位放电为内脏痛指标,观察向尾状核、中脑导水管周围灰质及杏仁内侧核内注入东亚钳蝎毒及在电解损毁3个核团前后PO内脏大神经诱发单位放电的变化。在损毁诸核之前刺激内脏大神经引起单位诱发放电,损毁诸核之后诱发放电减弱或消失,这与辽宁产东亚钳蝎毒注入诸核团中的作用相一致。表明蝎毒的作用部位与上述核团有关,更进一步证明蝎毒作用部位  相似文献   
102.
江门市乡镇集中式供水卫生现状分析   总被引:1,自引:0,他引:1  
为加强乡镇集中式供水卫生管理,进一步普及与提高农村的改水工作,我们按统一的调查方案,于1994 ̄1995年在全国范围内开展乡镇自来水厂调查登记和水质监测工作。据统计全市建成投产乡镇水厂68座,普及率77.3%,受益人口149.09万,占农村总人口62.5%,调查结果显示,水源总污染率为8.82%,在监测项目中主查细菌学指标合格率不高,丰、枯水期水源水平均合格率分别为40.0%和88.9%,而出厂水  相似文献   
103.
The in-vitro oestradiol (E2) and progesterone (P) production by corpora lutea (CL) obtained at sterilization from 30 untreated women and 43 women treated with norethisterone (NET) 300 micrograms daily was measured. The CL were obtained at different stages of the luteal phase in the untreated women [luteinizing hormone (LH) 0 to +3, n = 7; LH +4 to +7, n = 7; LH +8 to +11, n = 9; LH +12 to menses, n = 7] and on days LH +8 to +11 or cycle days 22 to 26 in the NET-treated women. In the treated women, four types of ovarian reaction were identified. Four women showed ovarian reaction Type A (completely inhibited ovarian activity), 14 women Type B (marked follicular activity, but no luteal function), 12 women Type C (normal follicular activity, followed by insufficient luteal function) and 13 women Type D (apparently normal follicular and luteal activity). The CL were incubated in Eagle's medium with and without stimulation by human chorionic gonadotrophin (HCG) for 2 and 4 h. In the untreated women, P and E2 production increased significantly with both incubation time and stimulation by HCG throughout the luteal phase, except in the late luteal phase (LH +12 to menses) where P increased (P less than 0.01) only after 4 h stimulation by HCG. The maximal production of P was found after 4 h incubation with HCG stimulation of CL tissue in the early-mid luteal phase (LH +4 to +7).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
104.
目的 探讨主动吸入药物烟对大鼠NO的影响。方法 制备大鼠主动吸烟模型 ,采用硝酸还原酶法测定各组大鼠血清、肺、心肌及脑组织的NO含量。结果 非药物烟组大鼠血清、肺、心肌及脑组织中NO含量明显低于非给烟对照组 ,药物烟高、中剂量组NO含量明显高于非药物烟组 ,接近非给烟对照组。结论 吸烟对大鼠血液、肺、心肌及脑组织有不同程度的损伤作用 ,使NO含量降低 ;药物烟具有一定的保护和防止NO含量降低的作用。  相似文献   
105.
Analysis of in vivo short TE 1H spectra is complicated by broad baseline signal contributions and resonance line-shape distortions. Although the assumptions of ideal metabolite resonance line-shapes and slowly varying baseline signals can be used to separate these signals, the presence of broad or asymmetric line-shapes can invalidate this model. More complex line-shape models are computationally expensive or difficult to constrain, particularly for the low signal-to-noise commonly found for in vivo MR spectroscopic imaging applications. In this study, two time-domain models for fitting variable spectral line-shapes are examined, one using B-splines and another using summed sinusoids. The methods were verified using both phantom and human data, and Monte Carlo simulations were used to evaluate variations in calculated metabolite amplitudes due to interactions between the baseline and line-shape estimations. Additional studies investigated the use of prior line-shape information, obtained from either a water MRSI measurement or calculations from B(0) maps, to determine parameter starting values or optimization constraints. Both line-shape models showed the ability to fit the variety of line-shapes present in both the phantom and human MRSI data, with similar or improved accuracy over a Gaussian line-shape model; however, this improvement resulted in only minor improvement for the high-SNR phantom data and moderate improvements in regions with asymmetry for the fitted in vivo metabolite images. The use of prior line-shape information was of most benefit when applied toward setting optimization constraints but was of limited benefit when used to define initial starting values.  相似文献   
106.
<正>This is a review of current situation of induced abortion and post abortion family planning service in China. Induced abortion is an important issue in reproductive health. This article reviewed the distribution of induced abortion in various time, areas, and population in China, and explored the character, reason, and harm to reproductive health of induced abortion. Furthermore, this article introduces the concept of Quality of Care Program in Family Planning, and discusses how important and necessary it is to introduce Quality of Care Program in Family Planning to China.  相似文献   
107.
This retrospective analysis reviews the clinical experience of a major urban referral hospital with diffuse malignant pleural mesothelioma during the 14-year period from 1973 through 1986. Seventy-five cases of definite or equivocal mesothelioma were identified. There were four cases of primary malignant peritoneal mesothelioma, seven cases of benign fibrous mesothelioma, and 64 cases of diffuse malignant pleural mesothelioma. In 43 cases (67%) of diffuse malignant pleural mesothelioma, there was historic evidence of asbestos exposure. In 21 cases (33%), there was no known history of asbestos exposure. An increase in annual incidence of diffuse malignant pleural mesothelioma was observed over the study period, from three cases in 1973 to ten cases in 1986. Despite greater awareness of this disease, the diagnosis remains a difficult one to establish given the nonspecific symptoms, signs and radiographic appearance, variable histologic appearance, and poor diagnostic sensitivity and specificity of thoracentesis and closed pleural biopsy. Thoracotomy, thoracoscopy, and CT-guided needle biopsies gave higher yields and are the diagnostic measures of choice when diffuse malignant pleural mesothelioma is suspected.  相似文献   
108.
文章介绍了从母亲体中采集到的心电信号,利用MATLAB软件对采集到的心电信号进行准确的数据实时处理,分离出胎儿心电(ECG)信号,实验结果表明,这种方法有一定的实用性。  相似文献   
109.
转型期的文学艺术总体格局出现了引人注目的变化 ,电视剧已成为百姓日常文化消费的主要对象 ;在艺术风格上呈现世俗化、平民化趋向的电视剧创作 ,同样要“代表先进文化的前进方向” ,这就要求创作者更新并优化观念。现代观念的涵义是丰富的 ,与时俱进的 ;一些电视剧的缺失都可以从中找到原因。而近几年涌现的一批在大众化、精品化方面取得重大进展的多种题材的电视剧 ,关键在于观念的突破带动了思想和艺术的创新  相似文献   
110.
谭家钊 《中国医院》2002,6(5):27-28
从高原部队医院实际出发,阐述了适应新形势谋求新发展应处理好的七个关系:即继承与创新的关系;坚持“姓军为兵的服务方向与对外有偿服务的关系;基础建设与人才建设的关系;日常医疗保障与科研的关系;发挥自身特色与学习借鉴的关系;硬件建设与软件建设的关系;科技研究与成果转化的关系。  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