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   18661篇
  免费   1965篇
  国内免费   27篇
耳鼻咽喉   152篇
儿科学   637篇
妇产科学   650篇
基础医学   2621篇
口腔科学   359篇
临床医学   2186篇
内科学   3790篇
皮肤病学   192篇
神经病学   1413篇
特种医学   581篇
外科学   2601篇
综合类   565篇
一般理论   43篇
预防医学   2279篇
眼科学   295篇
药学   1376篇
中国医学   15篇
肿瘤学   898篇
  2021年   315篇
  2020年   201篇
  2019年   298篇
  2018年   325篇
  2017年   262篇
  2016年   243篇
  2015年   276篇
  2014年   409篇
  2013年   621篇
  2012年   833篇
  2011年   941篇
  2010年   495篇
  2009年   469篇
  2008年   760篇
  2007年   812篇
  2006年   747篇
  2005年   790篇
  2004年   709篇
  2003年   696篇
  2002年   657篇
  2001年   597篇
  2000年   634篇
  1999年   542篇
  1998年   259篇
  1997年   214篇
  1996年   231篇
  1995年   208篇
  1994年   172篇
  1993年   161篇
  1992年   437篇
  1991年   478篇
  1990年   443篇
  1989年   413篇
  1988年   356篇
  1987年   390篇
  1986年   359篇
  1985年   340篇
  1984年   285篇
  1983年   239篇
  1982年   155篇
  1981年   149篇
  1980年   116篇
  1979年   194篇
  1978年   146篇
  1977年   151篇
  1976年   126篇
  1974年   182篇
  1973年   163篇
  1972年   131篇
  1970年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Influences on prescribing in non-fundholding general practices.   总被引:2,自引:1,他引:2       下载免费PDF全文
BACKGROUND: The experience from general practice fundholding suggests that financial incentives may influence prescribing; guidelines and hospital prescribing are two other suggested influences. AIM: A study was undertaken to establish general practitioners' attitudes to a financial prescribing incentive scheme, the presence and use of guidelines, and the influence of prescribing initiated within secondary care. METHOD: A postal questionnaire survey of non-fundholding general practices in the former Northern Region was conducted. RESULTS: Practices' thinking and subsequent decisions about the incentive prescribing scheme were most often influenced by discussions within the practice (45%). Those practices that achieved their savings under the incentive scheme were less likely than those not achieving savings to feel that the target was not achievable, the time scale was unacceptable, and that the philosophy behind the scheme was unacceptable. Forty-five per cent of practices received advice from neither a medical nor a pharmaceutical adviser; 27% of practices received advice from both, 12% from a medical adviser only and 16% from a pharmaceutical adviser only. Of the practices that tried to make their target savings, 91% intended to increase generic prescribing; fewer than one-third of practices mentioned any other measure. Prescribing guidelines were reported by a minority of practices, although reported rates of use were high when these were present. Clinical guidelines for three conditions, asthma, diabetes and hypertension, were present in more than 50% of practices; 25% of practices had no clinical guidelines. Hospital prescribing was reported as 'always' or 'usually' influencing prescribing for diabetes by 57% of respondents, ischaemic heart disease by 55%, peptic ulceration by 49%, asthma by 42% and hypertension by 39%. CONCLUSIONS: General practitioner prescribing is influenced by a complex web of factors, with no single factor pre-eminent. To understand this area further, there is a need to take each of these areas and ascertain the match between doctors' perceptions and actual practice.  相似文献   
92.
93.
A child is described with a de novo interstitial deletion of band 2p22 and a reciprocal translocation (3;7)(p21;q22). The child has mild developmental delay, coloboma of the right eye, and Hirschsprung's disease. The clinical and cytogenetic findings are described.  相似文献   
94.
Lactobacillus fermentum NCTC 6991 and Lactobacillus plantarum NCIB 7220 were grown in a chemostat in the diffusible fraction of complex medium at pH 6.0 with glucose limitation. Organisms grown at different dilution rates (D) were injected into rabbits, and the resultant antisera were examined for reactivity with antigens previously isolated from batch-grown organisms. For L. fermentum, antisera obtained on injecting cells grown at D = 0.5 h-1 contained a significantly higher level of antibody reacting with lipoteichoic acid and a lower level of antibody reacting with wall polysaccharide than did antisera obtained with slower-growing cells (D = 0.05 and 0.033). Antibodies to the cell wall polysaccharide were alpha-D-glucosyl specific and cross-reacted with dextran and alpha-D-glucosyl ribitol teichoic acid from L. plantarum. The immunogenicity of the ribitol teichoic acid and lipoteichoic acid components of L. plantarum was not influenced by injecting organisms grown at different rates. However, chemical and serological studies indicate that growth of L. plantarum in the diffusible fraction of complex medium results in a wall teichoic acid of lower glucose substitution. This apparently influences the specificity of the resultant antibodies so that some sera react much less with glucosyl-substituted lipoteichoic acid and dextran.  相似文献   
95.
Rapid detection of vancomycin-resistant enterococci.   总被引:4,自引:12,他引:4       下载免费PDF全文
Campylobacter blood agar with clindamycin incubated in 6% CO2 served as a medium to both screen for vancomycin resistance and select for presumptive enterococci. Colonies that grew on the medium were specifically identified as enterococci within 30 min by the pyroglutamyl-beta-naphthylamide and rapid bile esculin tests. The combination of a selective medium plus rapid enzyme substrate tests offered an inexpensive means to enumerate vancomycin-resistant enterococci from specimens by using readily available reagents.  相似文献   
96.
A case of postoperative prosthetic hip joint infection due to Campylobacter fetus subsp. fetus is described. Difficulties in isolation and antimicrobial susceptibility testing of this organism are discussed.  相似文献   
97.
BACKGROUND. The idiotypic determinants of the surface immunoglobulin of a B-cell lymphoma can serve as a clonal tumor-specific marker, which may have implications for immunotherapy. We sought to determine whether idiotype-specific immune responses against this autologous antigen could be induced in patients with B-cell lymphoma. METHODS. Nine patients were selected who had minimal residual disease or a complete remission after chemotherapy. Each received a series of subcutaneous injections of the immunoglobulin derived from his or her tumor cells (immunoglobulin-idiotype protein), which had been conjugated to a protein carrier and mixed with an immunologic adjuvant. RESULTS. In seven of the nine patients the injections induced sustained idiotype-specific immunologic responses of the humoral type (two patients), the cell-mediated type (four patients), or both (one patient). The use of an adjuvant was essential for these immune responses. The induced antibodies bound specifically to autologous immunoglobulin idiotype, inhibited the binding of murine monoclonal antiidiotype antibodies, and bound autologous tumor cells. Cell-mediated responses were demonstrated by the specific proliferation of immune peripheral-blood mononuclear cells to the soluble immunoglobulin-idiotype protein in vitro. The tumors of both of the patients with measurable disease regressed completely. Toxicity associated with the vaccine was minimal and consisted only of mild reactions at the site of intramuscular injection. CONCLUSIONS. These results demonstrate that autologous immunoglobulin idiotype can be formulated into an immunogenic, tumor-specific antigen in humans with B-cell lymphoma, and they provide the background for large-scale trials of active specific immunotherapy of this disease.  相似文献   
98.
Computers have gained rapid acceptance in general practice. A recent development has been the use of computers to run practice appointment systems. This study demonstrates the benefits of installing a computerized appointment system, with improved service for patients, and more efficient use of time by both doctors and receptionists.  相似文献   
99.
Isoflavones are plant compounds, proposed to have health benefits in a variety of human diseases, including coronary heart disease and endocrine-responsive cancers. Their physiological effects include possible antioxidant activity, therefore suggesting a role for isoflavones in the prevention of male infertility. The aim of this study was to test the antioxidant effects of the isoflavones genistein and equol on sperm DNA integrity, assessed in vitro after hydrogen peroxide-mediated damage, using the comet assay. Pre-treatment with genistein or equol at doses of 0.01-100 micromol/l significantly protected sperm DNA against oxidative damage. Both ascorbic acid (10-600 micromol/l) and alpha-tocopherol (1-100 micromol/l) also protected. Compared with ascorbic acid and alpha-tocopherol, added at physiological concentrations, genistein was the most potent antioxidant, followed by equol, ascorbic acid, and alpha-tocopherol. Genistein and equol added in combination were more protective than when added singly. Based on these preliminary data, which are similar to those observed previously in lymphocytes, these compounds may have a role to play in antioxidant protection against male infertility.  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