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   4596篇
  免费   443篇
  国内免费   13篇
耳鼻咽喉   11篇
儿科学   139篇
妇产科学   85篇
基础医学   674篇
口腔科学   106篇
临床医学   402篇
内科学   729篇
皮肤病学   44篇
神经病学   367篇
特种医学   225篇
外科学   813篇
综合类   127篇
一般理论   31篇
预防医学   361篇
眼科学   63篇
药学   531篇
中国医学   10篇
肿瘤学   334篇
  2022年   33篇
  2021年   74篇
  2020年   40篇
  2019年   68篇
  2018年   73篇
  2017年   46篇
  2016年   60篇
  2015年   74篇
  2014年   99篇
  2013年   155篇
  2012年   214篇
  2011年   209篇
  2010年   125篇
  2009年   114篇
  2008年   175篇
  2007年   180篇
  2006年   231篇
  2005年   204篇
  2004年   208篇
  2003年   177篇
  2002年   179篇
  2001年   183篇
  2000年   192篇
  1999年   169篇
  1998年   74篇
  1997年   75篇
  1996年   48篇
  1995年   55篇
  1994年   56篇
  1993年   57篇
  1992年   122篇
  1991年   112篇
  1990年   98篇
  1989年   82篇
  1988年   94篇
  1987年   70篇
  1986年   66篇
  1985年   62篇
  1984年   45篇
  1983年   41篇
  1982年   34篇
  1980年   31篇
  1979年   56篇
  1978年   41篇
  1977年   44篇
  1976年   38篇
  1975年   36篇
  1974年   32篇
  1973年   43篇
  1972年   27篇
排序方式: 共有5052条查询结果,搜索用时 15 毫秒
31.
32.
33.
An essential mode of contact between general practitioners (GPs) and hospital staff is the referral letter. This must be clear and concise with sufficient information to aid the GP, the consultant and the patient. In order to ensure this, a proposal was made for the use of a structured or standardized referral letter: a form letter. This report shows that form letters were shorter than typed letters. Form letters were also proven to contain more information than nonform letters.  相似文献   
34.
35.
36.
Parental and professional responses to questionnaires evaluating a paediatric disability service are reported and the viability of auditing structural, process, and outcome aspects of clinical practice are discussed. Expectations of waiting time to first appointment (met for only 52% of consumers) illustrate structural issues. Process issues are reflected in consumer reactions to outreach work (for example, 94% of parents and 84% of professionals found this supportive). Outcome measures such as consumer satisfaction with the service (76% of consumers reported being 'very satisfied' and 20% 'fairly satisfied') suggest that service aims are being met. Good concurrence of service aims with consumer needs is indicated by parental reasons for referral (for example, 75% for diagnostic help, 73% for a better understanding of the disorder, 88% for practical help), referrers' reasons (for example, 55% for a second diagnostic opinion, 45% due to lack of local expertise), and reports from most other professionals involved with the case that a similar service was not provided locally.  相似文献   
37.
The acute biochemical effects of the nephrotoxin p-aminophenol (PAP) were studied in detail using a combination of conventional bioanalytical and 1H-NMR spectroscopic methods. Dosing PAP (25–100 mg/kg) to male F344 rats resulted in a dose-related proximal nephropathy with consequent elevations in urinary enzymes, glucose, and urine total protein as shown by conventional methodology. 1H-NMR spectroscopy at 400 MHz of urine from PAP-treated rats also revealed a characteristic glycosuria, with concomitant amino aciduria. The increased excretion of these compounds indicates functional defects in the proximal tubule and reduced solute reabsorption efficiency. In addition, 1H-NMR urinalysis and conventional enzymatic analysis showed a dose-related lactic aciduria. Other changes detected by 1H-NMR included a dose-related reduction in the excretion of citrate (confirmed by a conventional biochemical method) and an increase in the excretion of acetate. The degree of abnormalities shown by 1H-NMR urinalysis agreed well with histopathological observations and conventional biochemical indices of nephrotoxicity. 1H-NMR urinalysis therefore serves to highlight changes in the excretion of low MW urine components not routinely studied by conventional biochemical analysis.Abbreviations ALP alkaline phosphatase - APAP paracetamol - BUN blood urea nitrogen - GFR glomerular filtration rate - GOT glutamate oxaloacetate transaminase - LAP leucine aminopeptidase - LDH lactate dehydrogenase - MW molecular weight - NAG N-acetyl--D-glucosaminidase - PAP p-aminophenol - ppm parts per million - TMAO trimethylamine N-oxide - UFR urine flow rate  相似文献   
38.
Hydrolysis of peptides within lumen of small intestine   总被引:2,自引:0,他引:2  
  相似文献   
39.
Grave's disease (GD) is a common disorder characterized by the presence of autoantibodies to the thyrotropin receptor. In the past, the exceedingly low expression of the thyrotropin receptor on thyrocytes has not allowed its purification in quantities sufficient to investigate the establishment of an animal model for this disease. In this study, we have purified the 398-amino acid, extracellular region of the human thyrotropin receptor (TSH-R.E) from insect cells using recombinant baculovirus, and explored its immunopathogenic properties in H-2b,d,q,k,s strains of mice. The receptor preparation was highly immunogenic since it elicited strong specific proliferative T cell responses as well as IgG responses in all strains tested. In addition, hyperimmunization with TSH-R.E induced (i) serum antibodies that blocked the binding of 125I-TSH to its receptor, a common feature of GD autoantibodies; and (ii) IgG that reacted with a synthetic peptide (residues 32-54) from the N-terminus of the receptor, a region implicated in the binding of thyroid stimulating antibodies. In SJL animals only, a weak antibody response to two other thyroid antigens, thyroglobulin and thyroid peroxidase, was also observed. The presence of these antibodies, however, was not accompanied by a detectable alteration in thyroid function as assessed by the measurement of serum TSH, T4 and iodine levels. Also mononuclear infiltration of the thyroid gland or morphological changes compatible with an activation state of thyrocytes were not apparent in TSH-R-challenged mice. In contrast, mice treated with the anti-oxidant aminotriazole showed a dramatic increase in serum TSH levels and an activated follicular epithelium. These data demonstrate that a highly immunogenic TSH-R.E in mice does not necessarily provide a proper stimulus for the induction of a hyper- or hypothyroid status as defined by hormonal or histological criteria. Main reasons for the inability to induce receptor-specific antibodies that affect thyroid function such as those generated in GD are likely to be the inappropriate folding of the recombinant extracellular domain of the receptor, or the xenogeneic nature of the autoantigen.  相似文献   
40.
Skin ligaments: regional distribution and variation in morphology   总被引:4,自引:0,他引:4  
Skin ligaments (SL) (L. retinacula cutis) are present extensively in the face, hands, feet, and in breast tissue, but have seldom been reported elsewhere in the body. The traditional histological view of the subcutaneous region is that it comprises a matrix of loose connective tissue devoid of fibrous specializations. The purpose of this study was to determine the structure and distribution of skin ligaments. Eight embalmed cadavers (3 males, 5 females, 69-90 years of age) were used in this study. Tissue was prepared using the E12 plastination technique. Macroscopic and microscopic examination demonstrated the widespread presence in the limbs and most of the rest of the body of fibrous strands linking the base of the dermis and the superficial fibers of the underlying deep fascia. The morphology and distribution of these skin ligaments were similar in the individuals examined. Variations in the structure of the skin ligaments depended on the presence of underlying muscle, neurovascular bundles, intermuscular septa and adipose tissue. We conclude that skin ligaments are complex fibrous structures that are present over most of the body. They form an extensive peripheral network in the subcutaneous fat. These 'ligaments' seem to provide an anchorage of skin to deep fascia that is flexible and yet resistant to mechanical loading from multi-directional forces. The use of the E12 plastination technique coupled with fluorescent confocal microscopy has been of benefit in visualizing and delineating SLs from other soft tissue structures in three planes.  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