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   49551篇
  免费   3846篇
  国内免费   627篇
耳鼻咽喉   225篇
儿科学   2208篇
妇产科学   1076篇
基础医学   4079篇
口腔科学   392篇
临床医学   5106篇
内科学   13413篇
皮肤病学   765篇
神经病学   3346篇
特种医学   685篇
外科学   4991篇
综合类   2719篇
现状与发展   1篇
一般理论   16篇
预防医学   7723篇
眼科学   1645篇
药学   2265篇
  4篇
中国医学   372篇
肿瘤学   2993篇
  2024年   75篇
  2023年   572篇
  2022年   430篇
  2021年   689篇
  2020年   640篇
  2019年   301篇
  2018年   1011篇
  2017年   1011篇
  2016年   1135篇
  2015年   1107篇
  2014年   1011篇
  2013年   1438篇
  2012年   3272篇
  2011年   4608篇
  2010年   1955篇
  2009年   1607篇
  2008年   3739篇
  2007年   3607篇
  2006年   3176篇
  2005年   3380篇
  2004年   4446篇
  2003年   4298篇
  2002年   3157篇
  2001年   2335篇
  2000年   865篇
  1999年   653篇
  1998年   613篇
  1997年   519篇
  1996年   275篇
  1995年   194篇
  1994年   204篇
  1993年   203篇
  1992年   188篇
  1991年   130篇
  1990年   139篇
  1989年   110篇
  1988年   100篇
  1987年   98篇
  1986年   76篇
  1985年   54篇
  1984年   48篇
  1983年   35篇
  1982年   40篇
  1981年   42篇
  1980年   28篇
  1979年   23篇
  1978年   25篇
  1975年   19篇
  1974年   25篇
  1968年   19篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
91.
92.
93.
Because of the essential role of transporter associated with antigen processing (TAP1 or TAP2) molecule in antigen processing, the implication of its polymorphism as a factor involved in human diseases and the possible genetic variation at this locus among ethnically diverse populations, we underwent a study to analyze the full extent of TAP1 polymorphism in an indigenous Zimbabwean population (Shona ethnic group). Using single-stranded conformation polymorphism and DNA direct sequencing procedures, we detected the presence of 11 nucleotide sequence variations in the entire coding region of TAP1. Of these variants, eight are nonconservative substitutions with respect to amino acid composition and are located in a critical part of the protein that could modulate its function. Five new polymorphic sites were identified in exon 1 (codons 7 Pro --> Ser, 17 Gly --> Arg, 141 Val --> Val), exon 6 (codon 419 Gly --> Cys), and exon 7 (codon 487 Arg --> Arg). Significant differences were seen in the distribution of TAP1*0201 and TAP1*0401 alleles, and codon 333 (Ile --> Val) polymorphism among African and non-African populations. Thus, TAP1 polymorphism has evolved differently among populations presumably because of the evolutionary pressures generated by prevalent pathogens in these geographically distinct regions.  相似文献   
94.
Summary Clinically relevant events possibly attributable to drug exposure have been monitored prospectively over a period of six months in 27 general intensive care units. Fifty-four events attributed to drugs were reported in 51 patients during their stay in hospital, corresponding to an overall incidence of 1.35%. The behaviour of the physicians following attribution of the events to a prescribed drug is analyzed and discussed in detail with respect to its relationship to the quality and severity of the reaction, and the classes of drugs. Twenty-four of the 4537 monitored admissions during the six months were due to life-threatening emergencies linked to the administration of drugs (14) and radio-contrast media (10) (overall incidence 0.5%). While the clinical burden attributable to adverse drug reactions in Intensive Care Units appears to be relatively small, the analysis shows that there is ample room for a greater reduction in their incidence. Coordinators: Drs M. L. Farina and G. Tognoni, Istituto di Ricerche Farmacologiche Mario Negri, Milan; Dr F. Procaccio, Neurosurgical ICU, Ospedale Ca' Granda, Niguarda, Milan.Investigators: Drs G. Barusco, Rovigo; F. Bassi, Milan; L. Bianchetti, Torino; E. Carchietti, Udine; G. Chilloni, Reggio Emilia; G. Costantini, Savigliano (CN); P. Ferrero, Aosta; E. Geat, Trento; F. Gorgerino, Torino; A. Lusini, Empoli (FI); G. Mantovani, Ferrara; S. Marchi, Bologna; P. Marcovigi, Forli; G. Marraro, Merate (CO); F. Merlo, Vicenza; E. Pagni, Bagno a Ripoli (FI); R. Pellegrino, Cuneo; C. Peruselli, Milan; A. Piovesano, Pordenone; R. Rinaldo, Cremona; R. Ruggerini, Piacenza; S. Sammartino, Torino; A. Sartore, Cittadella (PD); A. Scaglioli, Carpi (MO); G. Scopa, Terni; G. Zeffiro, Treviso; P. Zuccoli, Parma  相似文献   
95.
In 1984 the Council of the British Medical Association set up a working party, chaired by J.P. Quillam, to investigate claims that doctors in some countries were cooperating with the use of torture as a routine instrument of repression. The conclusions and recommendations of the working party's recently published report are reproduced here, along with a list of the members of the working party. Among the report's conclusions [which are reproduced also in the British Medical Journal 1986 Mar 15; 292(6522): 781-782] are that doctors have a responsibility to support any practitioner who refuses to keep silent about abuses of human rights, to check for signs of physical abuse of prisoners, and to publicize any violations of the Declaration of Tokyo. Physicians are also encouraged to offer their services to organizations such as the Medical Foundation for the Care of Victims of Torture.  相似文献   
96.
The role of surgery as an additional risk in transmitting post-transfusion hepatitis was investigated in a retrospective study on acute hepatitis occurring in 77 transfused patients, 293 transfused and operated patients and 243 hepatitis cases with history of surgery without transfusion.Hepatitis A patients admitted to the same centres in the same period were utilized as controls. In transfused patients the percentage of NANB hepatitis was higher than that of type B (61.0% vs. 36.4%), while in the operated not transfused group the percentage of type B was twice that of type NANB (63.4% vs. 32.5%).In transfused and operated cases intermediate values were observed. The age-adjusted measures of association between exposures and the different hepatitis types showed a lack of effect of transfusion and a dominant role of surgery in transmitting type B hepatitis. In contrast, NANB post-transfusional cases were actually a mixture of post-transfusional and post-surgical cases, since both these exposures were found to be significantly associated with the disease.Our results suggest that studies on the incidence and the etiology of post-transfusion hepatitis should take into account the risk of surgical exposure which might have occurred.Corresponding author.  相似文献   
97.
Metadata, the term, may be new but metadata, the concept, is not new. For purposes of this paper, the term metadata is defined as the data used to define, store, retrieve, combine, analyze, and present the data values (the “real” data, so to speak). As clinical research studies get larger, it becomes desirable to use automated managers of the metadata. The Program on the Surgical Control of the Hyperlipidemias (POSCH), a national multiclinic clinical trial, manages most of its metadata manually but has been experimenting with ways to more fully automate them. Its Information Management System (IMS) is described with special emphasis on how it manages the metadata. The case is presented for further automation and standardization of metadata in large clinical research studies so that costs can be contained and smaller increments of “progress” can be measured. The concept of a Metadatabase Management System (MDBMS) is developed and illustrated using POSCH.  相似文献   
98.
人工流产术前宫颈及子宫内膜麻醉的镇痛效果探讨   总被引:1,自引:0,他引:1  
目的 探讨宫颈与子宫内膜两部位联合麻醉、普鲁卡因与利多卡因两药物配合应用在人工流产术中的镇痛效果。方法 人工流产术前对麻醉组 10 6例行普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉。术中记录受术者腹痛程度、无阻力插入宫颈内口的扩张器号、出血量、人流综合征例数等指标。按照世界卫生组织规定疼痛标准及人工流产综合征反应进行评价 ,同期选择按传统机械扩宫法 10 4例做对照。结果 麻醉组镇痛有效率95 3% ,宫口松驰有效率 95 3% ,人流综合征无 1例发生。两组比较P均 <0 0 0 1。两组出血量比较无差异 ,无利多卡因毒性反应发生。结论 人工流产术前普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉镇痛效果显著 ,可大大降低人流综合征的发生 ,避免利多卡因的毒性反应  相似文献   
99.
High-risk combinations of recipient and graft characteristics are poorly defined for liver retransplantation (reLT) in the current era. We aimed to develop a risk model for survival after reLT using data from the European Liver Transplantation Registry, followed by internal and external validation. From 2006 to 2016, 85 067 liver transplants were recorded, including 5581 reLTs (6.6%). The final model included seven predictors of graft survival: recipient age, model for end-stage liver disease score, indication for reLT, recipient hospitalization, time between primary liver transplantation and reLT, donor age, and cold ischemia time. By assigning points to each variable in proportion to their hazard ratio, a simplified risk score was created ranging 0–10. Low-risk (0–3), medium-risk (4–5), and high-risk (6–10) groups were identified with significantly different 5-year survival rates ranging 56.9% (95% CI 52.8–60.7%), 46.3% (95% CI 41.1–51.4%), and 32.1% (95% CI 23.5–41.0%), respectively (< 0.001). External validation showed that the expected survival rates were closely aligned with the observed mortality probabilities. The Retransplantation Risk Score identifies high-risk combinations of recipient- and graft-related factors prognostic for long-term graft survival after reLT. This tool may serve as a guidance for clinical decision-making on liver acceptance for reLT.  相似文献   
100.
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