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   8992篇
  免费   721篇
  国内免费   11篇
耳鼻咽喉   112篇
儿科学   369篇
妇产科学   329篇
基础医学   1118篇
口腔科学   279篇
临床医学   901篇
内科学   1671篇
皮肤病学   279篇
神经病学   736篇
特种医学   550篇
外科学   1134篇
综合类   224篇
一般理论   7篇
预防医学   783篇
眼科学   69篇
药学   573篇
中国医学   14篇
肿瘤学   576篇
  2021年   114篇
  2019年   102篇
  2018年   126篇
  2017年   97篇
  2016年   95篇
  2015年   143篇
  2014年   188篇
  2013年   294篇
  2012年   358篇
  2011年   358篇
  2010年   234篇
  2009年   214篇
  2008年   339篇
  2007年   357篇
  2006年   333篇
  2005年   347篇
  2004年   333篇
  2003年   345篇
  2002年   306篇
  2001年   290篇
  2000年   302篇
  1999年   254篇
  1998年   129篇
  1997年   128篇
  1996年   124篇
  1995年   113篇
  1994年   120篇
  1993年   103篇
  1992年   196篇
  1991年   219篇
  1990年   209篇
  1989年   206篇
  1988年   211篇
  1987年   223篇
  1986年   215篇
  1985年   186篇
  1984年   155篇
  1983年   132篇
  1982年   92篇
  1981年   95篇
  1980年   87篇
  1979年   108篇
  1978年   85篇
  1977年   71篇
  1976年   69篇
  1975年   69篇
  1974年   78篇
  1973年   92篇
  1972年   74篇
  1970年   78篇
排序方式: 共有9724条查询结果,搜索用时 15 毫秒
51.
52.
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.  相似文献   
53.
54.
Perceptual dysfunction in hemiplegia and automobile driving.   总被引:1,自引:0,他引:1  
Sixteen post-stroke, hemiplegic patients, who requested that they be allowed to return to driving, were extensively evaluated by a physiatrist, psychologist, occupational therapist, and driver training specialist. After they completed a driver training program, the patients were divided into three groups based on their driving program success and follow-ups. Significant differences in the psychological test results were found between Group I (those who drove without any difficulty) and Groups II and III (those who drove limited distance or who failed driver training). Results suggest that patients with significant cognitive and perceptual problems who take training and limit their driving can be safe drivers when they return to driving.  相似文献   
55.
56.
57.
58.
The guanylnucleotide specificity of muscarinic acetylcholine receptor (MR) inhibitory coupling to cardiac adenylate cyclase (AC) was investigated under low MgCl2 (i.e., 0.5 mM) conditions. In purified cardiac sarcolemma, carbachol maximally inhibited AC activity 60% in the presence of GTP. Carbachol-dependent inhibition in the presence of guanosine 5'-O-(3-thiotriphosphate (GTP gamma S) or guanylylimidodiphosphate [Gpp(NH)p] was of lesser magnitude (i.e., 30%) and was evident only during short incubation periods. Of greater interest, carbachol maximally inhibited AC activity in the presence of GDP and guanosine 5'-O-(2-thiodiphosphate (GDP beta S) by 35 and 60%, respectively. Control studies ruled out transphosphorylation of GDP and GDP beta S by nucleoside diphosphate kinase or guanylnucleoside triphosphate contamination as reasons for the inhibitory effects of GDP and GDP beta S. Furthermore, isoproterenol stimulated AC in the presence of GTP, GTP gamma S, and Gpp(NH)p but not in the presence of GDP or GDP beta S. Therefore, GDP and GDP beta S may serve as agonists on MR-activated Gi but not on beta-adrenergic receptor-activated Gs in these membranes. Time course studies revealed that carbachol-dependent inhibition of AC in the presence of either GTP or GDP occurred without a detectable lag period, and this inhibition was rapidly reversed by atropine. In contrast, a 1-2-min lag time was required for carbachol- and GDP beta S-dependent inhibition of AC to occur, and inhibition, once developed, was only partially and slowly reversed by atropine. Preincubation of sarcolemma with carbachol and GDP beta S, in the absence of ATP or under nonphosphorylating conditions, eliminated the lag time for inhibition of AC activity. Although it is unlikely that GDP and GDP beta S have physiological relevance of MR-Gi-AC coupling, these studies provide unique insights into this coupling mechanism in cardiac membranes.  相似文献   
59.
Using pulsed-field gel electrophoresis (PFGE) and 16S rRNA (rrn) analysis (ribotyping), the in vivo derivation of strains of Salmonella enteritidis PTs 9a and 7 from a strain of S. enteritidis PT 4 has been demonstrated. All strains were isolated from a single patient over a 6-week period. Further studies have demonstrated that in terms of pulsed-field profile and ribotype, the genotypes of the patient-derived strains differed from those of the reference strains of the respective phage types. It is concluded that when used in combination, these methods can provide evidence of phylogenetic relationships in apparently unrelated S. enteritidis phage types isolated during pathogenesis of disease.  相似文献   
60.
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