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   9451篇
  免费   802篇
  国内免费   16篇
耳鼻咽喉   57篇
儿科学   191篇
妇产科学   129篇
基础医学   1547篇
口腔科学   218篇
临床医学   812篇
内科学   2026篇
皮肤病学   206篇
神经病学   1142篇
特种医学   583篇
外科学   847篇
综合类   50篇
一般理论   9篇
预防医学   922篇
眼科学   157篇
药学   529篇
中国医学   20篇
肿瘤学   824篇
  2023年   66篇
  2022年   108篇
  2021年   236篇
  2020年   148篇
  2019年   228篇
  2018年   227篇
  2017年   240篇
  2016年   250篇
  2015年   297篇
  2014年   349篇
  2013年   457篇
  2012年   676篇
  2011年   696篇
  2010年   423篇
  2009年   395篇
  2008年   579篇
  2007年   595篇
  2006年   517篇
  2005年   510篇
  2004年   440篇
  2003年   408篇
  2002年   369篇
  2001年   167篇
  2000年   152篇
  1999年   168篇
  1998年   92篇
  1997年   72篇
  1996年   64篇
  1995年   67篇
  1994年   60篇
  1993年   55篇
  1992年   108篇
  1991年   94篇
  1990年   107篇
  1989年   86篇
  1988年   72篇
  1987年   64篇
  1986年   59篇
  1985年   56篇
  1984年   42篇
  1983年   37篇
  1982年   31篇
  1981年   44篇
  1980年   31篇
  1979年   35篇
  1978年   28篇
  1977年   24篇
  1975年   25篇
  1974年   32篇
  1973年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Killing of schistosomula by taurine chloramine and taurine bromamine   总被引:2,自引:0,他引:2  
Eosinophils generate hypochlorous acid when stimulated with opsonized particles. The hypochlorous acid can react with beta-amino acids such as taurine to produce chloramines with a long lifetime. In the presence of bromide, eosinophils generate hypobromous acid which can react with taurine to generate taurine bromamine. As taurine is abundantly present in leukocytes, eosinophils have the potential to generate taurine chloramine or taurine bromamine. With regard to the role of eosinophils in killing schistosomula, we have shown that both taurine chloramine and taurine bromamine in physiological concentrations are able to kill the schistosomula of Schistosoma mansoni.  相似文献   
6.
The parafollicular-cell (C-cell) hormone calcitonin (CT) can preserve or even augment skeletal mass by inhibiting osteoclast-mediated bone resorption. The possibility of an additional anabolic skeletal influence has also been raised: C cells might, via CT or other secretory products, affect osteoblast-mediated bone formation. The 57-residue amino-terminal procalcitonin cleavage peptide, N-proCT, has recently been identified in human and rat C cells, where it is made and secreted in equimolar amounts with CT. The coelaboration of N-proCT and CT and N-proCT's sequence conservation during evolution prompted us to investigate the potential skeletal bioactivity of N-proCT. We found that synthetic human N-proCT, at nanomolar concentrations, stimulated proliferation of normal and neoplastic human osteoblasts. At maximally effective doses, human N-proCT caused more than a 100% increase above the control rate of DNA synthesis, an effect comparable to the maximal growth effect of insulin, a potent mitogen for osteoblasts. Human N-proCT exerted a similar maximal mitogenic effect in chicken osteoblast cultures but at 1000-fold greater concentrations than in human bone-cell cultures. The bone-cell action of N-proCT was potentiated with insulin with a greater than 200% increase in DNA synthesis at high insulin concentrations. In sharp contrast to these findings for N-proCT, the other bioactive C-cell peptides, CT and somatostatin, showed no mitogenic effects in human or chicken osteoblast cultures. Our results indicate that the action of N-proCT on cultured bone cells is separate from and potentiated by insulin, a known growth factor. Unlike insulin and related growth factors such as insulin-like growth factor I, N-proCT is not mitogenic in skin fibroblast cultures. We propose that N-proCT is a C-cell hormone that promotes bone formation via stimulatory actions on osteoblasts and preosteoblasts.  相似文献   
7.
8.
AIMS: To evaluate the predictive accuracy of the Systematic Coronary Risk Evaluation (SCORE) project high-risk function in Norway. METHODS AND RESULTS: We included 57 229 individuals screened in 1985-1992 from two population-based surveys in Norway (age groups 40-49, 50-59, and 60-69 years). The data have been linked to the Norwegian Cause of Death Registry. The SCORE high-risk algorithm for the prediction of 10-year cardiovascular disease (CVD) mortality was applied, and the risk factors entered into the model were age, sex, total cholesterol, systolic blood pressure, and smoking (yes/no). The number of expected events estimated by the SCORE model (E) was compared with the observed numbers (O). The SCORE low-risk algorithm was studied for comparison. In men, the observed number of CVD deaths was 718, compared with 1464 estimated by the SCORE high-risk function (O/E ratios 0.53, 0.53 and 0.45, for age groups 40-49, 50-59 and 60-69, respectively). In women, the observed and expected numbers were 226 and 547. The O/E ratios decreased with age (ratios 0.60, 0.45 and 0.37, respectively), i.e. the overestimation increased with age. The low-risk function predicted reasonably well for men (ratios 0.85, 0.92 and 0.79, respectively), whereas an overestimation was found for women aged 50-59 and 60-69 years (ratios 0.69 and 0.56, respectively). CONCLUSION: The SCORE high-risk model overestimated the number of CVD deaths in Norway. Before implementation in clinical practice, proper adjustments to national levels are required.  相似文献   
9.
Out of 169 patients with streptococcal tonsillitis treated with phenoxymethylpenicillin, 13 (8%) developed a new clinical infection with the same streptococcal strain within 2 weeks of completing the therapy (clinical treatment failure) and 24 (14%) were clinically healthy but harboured the same streptococcal strain after treatment (bacterial treatment failure). Patients with clinical treatment failure showed beta-lactamase activity in their saliva pellet significantly more often than patients with bacterial treatment failure, healed streptococcal tonsillitis or non-streptococcal tonsillitis as well as healthy controls. In an interference study, clinical treatment failures were compared with healthy streptococcal carriers, i.e. persons living in the same household and harbouring the same beta-streptococcal strain. 11/12 healthy carriers had alpha-streptococci with interfering activity against their own beta-streptococcal strain, while the corresponding figure for the clinical treatment failures was 2/13. Furthermore, 6/12 healthy carriers had beta-streptococci inhibiting their own alpha-strains, while the streptococci in 11/13 clinical treatment failures had this ability. The beta-lactamase activity and the interference between alpha- and beta-streptococci may be a contributory cause to treatment failure in streptococcal tonsillitis.  相似文献   
10.
Eight children with the syndrome of Gilles de la Tourette underwent a neuropsychological assessment. The results were compared with those of eight children with proven lesions of the right cerebral hemisphere and with eight children with learning disabilities without neurological disturbances. Our findings do not support organicity or dysfunctions of the right hemisphere in children with Gilles de la Tourette syndrome.  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