全文获取类型
收费全文 | 388204篇 |
免费 | 50255篇 |
国内免费 | 16748篇 |
专业分类
耳鼻咽喉 | 7164篇 |
儿科学 | 8313篇 |
妇产科学 | 7239篇 |
基础医学 | 31111篇 |
口腔科学 | 5647篇 |
临床医学 | 56782篇 |
内科学 | 85797篇 |
皮肤病学 | 10079篇 |
神经病学 | 27812篇 |
特种医学 | 14690篇 |
外国民族医学 | 96篇 |
外科学 | 66385篇 |
综合类 | 34281篇 |
现状与发展 | 117篇 |
一般理论 | 45篇 |
预防医学 | 21906篇 |
眼科学 | 9927篇 |
药学 | 25014篇 |
164篇 | |
中国医学 | 10896篇 |
肿瘤学 | 31742篇 |
出版年
2024年 | 1350篇 |
2023年 | 7964篇 |
2022年 | 9798篇 |
2021年 | 14309篇 |
2020年 | 14110篇 |
2019年 | 9566篇 |
2018年 | 15032篇 |
2017年 | 14022篇 |
2016年 | 14737篇 |
2015年 | 18169篇 |
2014年 | 27729篇 |
2013年 | 27033篇 |
2012年 | 22720篇 |
2011年 | 24422篇 |
2010年 | 21739篇 |
2009年 | 23236篇 |
2008年 | 18325篇 |
2007年 | 16630篇 |
2006年 | 18631篇 |
2005年 | 16020篇 |
2004年 | 11484篇 |
2003年 | 9518篇 |
2002年 | 8581篇 |
2001年 | 9730篇 |
2000年 | 9073篇 |
1999年 | 9577篇 |
1998年 | 7255篇 |
1997年 | 7089篇 |
1996年 | 6121篇 |
1995年 | 5764篇 |
1994年 | 4153篇 |
1993年 | 3045篇 |
1992年 | 3652篇 |
1991年 | 3391篇 |
1990年 | 2711篇 |
1989年 | 2616篇 |
1988年 | 2271篇 |
1987年 | 2020篇 |
1986年 | 1821篇 |
1985年 | 1457篇 |
1984年 | 1034篇 |
1983年 | 897篇 |
1982年 | 736篇 |
1981年 | 598篇 |
1980年 | 547篇 |
1979年 | 548篇 |
1978年 | 469篇 |
1977年 | 508篇 |
1975年 | 362篇 |
1972年 | 375篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
211.
目的 对胸腰段脊柱脊髓,马尾神经损伤患者的外科治疗及几种内固定方法的疗效进行探讨。方法 对166例患者的治疗进行回顾分析。该组患者中椎体爆裂性骨折37例,椎体压缩骨折超二分之一109例,椎体骨折脱位14例,多节段或跳跃骨折6例,脊髓损伤按Frankel分级,A级59例,B级46例,C级42例,D级19例,治疗采用后路减压复位122例,前路减压复位,髂骨植骨融合44例。结果 术后123例获3-18个月随访,随访患者中随4例RF钉断裂,5例Harrington上钩脱落,6例棍断裂,其余患者内固定稳固,脊髓,马尾神经恢复,除35例仍为A级外,余脊髓神经功能恢复1-3个级别。结论 各种不同内固定可保持或增强脊柱的稳定,胸腰段脊柱脊髓损伤的外科治疗应根据骨折类型,脊髓及马尾神经损伤程度选择手术入路及内固定材料。 相似文献
212.
目的:观察肝癌形成过程中明胶酶表达(蛋白及mRNA水平)的动态变化,探索明胶酶在肝癌生长浸润中的作用。方法:应用免疫组化法、明胶酶谱法和RT-PCR法对大鼠肝癌形成过程中各期明胶酶表达情况进行观察,并与正常对照组进行比较分析。结果:正常肝组织及肝硬化组织内明胶酶有表达,肝癌形成后主要在癌细胞内表达;明胶酶原在正常肝组织中有低表达,诱癌过程中呈持续增高趋势;明胶酶-2mRNA与其酶蛋白表达趋向一致。结论:在肝癌形成过程中明胶酶转录和翻译水平均呈持续增高趋势。 相似文献
213.
214.
CT扫描及超声内镜术前评价进展期食管癌 总被引:3,自引:0,他引:3
目的比较胸部螺旋CT增强扫描及微探头超声内镜 (MPS)检查在评价进展期食管癌中的价值。方法 :32例进展期食管癌术前行CT扫描和MPS检查并与术后病理学比较。结果 :CT扫描能发现 84 .4 %的食管癌病灶 ,但不能准确诊断癌肿浸润深度 ,诊断纵隔结构受侵准确率 75 % ,发现区域淋巴结转移的敏感性90 .9% ,特异性 81.8% ,对纵隔内远处淋巴结转移诊断准确率 80 %。MPS检查能检出所有病例的进展期食管癌病灶 ,癌肿浸润深度诊断准确率 81.3% ,诊断纵隔结构受侵准确率 5 0 % ,诊断区域淋巴结转移敏感性81.8% ,特异性 72 .7% ,而对纵隔内远处转移的淋巴结均未能探及。结论 :CT扫描在评价进展期食管癌纵隔内结构受侵及远处淋巴结转移的意义较大。而MPS检查在判断癌肿管腔浸润深度的准确率较高。 相似文献
215.
216.
Jeffrey H. Coben MD 《Academic emergency medicine》2002,9(11):1176-1183
OBJECTIVE: To obtain consensus among a panel of experts on performance measures useful for evaluating the quality of hospital-based domestic violence (DV) programs. METHODS: The Delphi process of consensus development was used with a panel of 18 experts including DV researchers, program planners, and advocates. Three rounds were conducted over a period of six months, with each round involving the completion of a written questionnaire. Panelists were instructed to concentrate on structure and process measures of DV program performance. Health outcome measures were not considered. During each round, panelists rated (scale of 1-5) their level of agreement with each measure, in terms of the measure's usefulness for evaluating hospital-based DV programs. Data were entered into SPSS on a personal computer and frequency distributions, measures of central tendency, and variance were computed for each measure. Consensus development was defined as a reduction in the item-specific variance from one round to the next. RESULTS: A total of 37 performance measures were agreed upon. These measures fell within nine different domains of DV program activities, including: Policies and Procedures, Hospital Physical Environment, Hospital Cultural Environment, Training of Providers, Screening and Safety Assessment, Documentation, Intervention Services, Evaluation Activities, and Collaboration. CONCLUSIONS: A number of measures have been identified as useful for evaluating hospital-based DV programs. Use of these measures should assist researchers, program planners, and administrators in assessing the quality of hospital-based DV programs. 相似文献
217.
David C. Cone MD Susan M. Nedza MD MBA James J. Augustine MD Steven J. Davidson MD MBA 《Academic emergency medicine》2002,9(11):1085-1090
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference. 相似文献
218.
The effects of intracellular Ca2+ (Ca2+i) on K+ currents in hippocampal cells were examined using acutely isolated cells obtained from adult guinea pigs. Whole-cell voltage-clamp recordings were carried out in a configuration that allowed a continuous perfusion of the intracellular medium. Recording media were made to block inward currents and allowed selective activation of K(+)-dependent outward currents. Voltage-dependent outward currents consisted of an initial rapidly decaying component followed by a sustained component. The time constant of decay of the transient current was about 25 msec, and previous studies (Numann et al., 1987) showed that the kinetic and pharmacological properties of this current closely resembled the A current recorded in invertebrate neurons (Connor and Stevens, 1971; Thompson, 1982). Intracellular perfusion of hippocampal cells with a solution containing elevated Ca2+ (about 4.5 x 10(-4) M) elicited outward currents at the holding potential (-45 to -55 mV) and produced changes in voltage-dependent K+ currents. The transient outward current (IA) activated by depolarization was suppressed with increases in Ca2+i. Delayed, sustained K+ currents were greatly potentiated. Data also showed that, among the 3 effects elicited by Ca2+i, suppression of IA was most sensitive to Ca2+i elevation. Previous results (Numann et al., 1987) showed that IA had a lower threshold (about -45 mV) than sustained currents (about -40 mV). By using low levels of depolarization (-40 mV), IA can be selectively activated, and the suppressive effect of Ca2+i on IA was confirmed on the kinetically isolated IA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
219.
Therapy of human cervical carcinoma with monoclonal antibody-Pseudomonas exotoxin conjugates. 总被引:1,自引:0,他引:1
Pseudomonas exotoxin A (PE) linked to the F(ab')2 fragment of 1H10, a murine monoclonal antibody recognizing a carbohydrate epitope of a glycoconjugate expressed on the surface of human cervical carcinoma tumor cells, was evaluated for in vitro and in vivo activity. PE can kill cells by ADP-ribosylating elongation factor 2 thus inhibiting protein synthesis. Disulfide- as well as thioether-linked immunotoxins (1H10-PE) killed cervical carcinoma cells in vitro and were 20-160 times more inhibitory to target than to control cells. Cell killing was antibody mediated as demonstrated by the reduction of 1H10-PE growth inhibition to target CaSki cells by free 1H10 F(ab')2. In addition, a control antibody immunotoxin was nontoxic to CaSki cells. Thioether-linked 1H10-PE administered either i.v. or i.p. suppressed the growth of established solid s.c. cervical carcinoma tumors xenografted in nude mice for over 30 days. Treatment with antibody alone or a control immunotoxin had no significant effect on tumor growth. Administration of immunotoxin i.p. was associated with less toxicity than administration i.v., but i.v. injections were more effective at suppressing the growth of established solid tumors. 相似文献
220.
Xiaoguang Chen Yi Li Lei Wang Mark Katakowski Lijie Zhang Jieli Chen Yongxian Xu Subhash C. Gautam Michael Chopp 《Neuropathology》2002,22(4):275-279
Intravenous administration of human bone marrow stromal cells (hMSCs) after middle cerebral artery occlusion (MCAo) in rats provides functional benefit. We tested the hypothesis that these functional benefits are derived in part from hMSC production of growth and trophic factors. Quantitative sandwich enzyme‐linked immunosorbent assay (ELISA) of hMSCs cultured with normal and MCAo brain extracts were performed. hMSCs cultured in supernatant derived from ischemic brain extracts increased production of brain‐derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). These neurotrophins and angiogenic growth factors increased in a post‐ischemia time‐dependent manner. The hMSC capacity to increase expression of growth and trophic factors may be the key to the benefit provided by transplanted hMSCs in the ischemic brain. 相似文献