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   1992篇
  免费   152篇
  国内免费   2篇
耳鼻咽喉   32篇
儿科学   64篇
妇产科学   15篇
基础医学   247篇
口腔科学   170篇
临床医学   298篇
内科学   374篇
皮肤病学   34篇
神经病学   128篇
特种医学   23篇
外科学   172篇
综合类   25篇
一般理论   1篇
预防医学   275篇
眼科学   12篇
药学   141篇
肿瘤学   135篇
  2023年   8篇
  2022年   13篇
  2021年   29篇
  2020年   21篇
  2019年   33篇
  2018年   38篇
  2017年   42篇
  2016年   39篇
  2015年   43篇
  2014年   78篇
  2013年   101篇
  2012年   145篇
  2011年   167篇
  2010年   88篇
  2009年   67篇
  2008年   116篇
  2007年   168篇
  2006年   119篇
  2005年   137篇
  2004年   151篇
  2003年   142篇
  2002年   120篇
  2001年   13篇
  2000年   13篇
  1999年   20篇
  1998年   28篇
  1997年   28篇
  1996年   25篇
  1995年   20篇
  1994年   15篇
  1993年   14篇
  1992年   12篇
  1991年   4篇
  1990年   7篇
  1989年   6篇
  1988年   4篇
  1987年   7篇
  1985年   4篇
  1984年   7篇
  1983年   4篇
  1982年   11篇
  1981年   3篇
  1980年   7篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1976年   6篇
  1966年   3篇
  1960年   2篇
  1936年   2篇
排序方式: 共有2146条查询结果,搜索用时 922 毫秒
11.
Long-term use of cyclosporine after renal transplantation results in nephrotoxicity and an increased cardiovascular risk profile. Tacrolimus may be more favorable in this respect. In this randomized controlled study in 124 renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on renal function, cardiovascular risk factors, and perceived side-effects were investigated after a follow-up of 2 years. After conversion from cyclosporine to tacrolimus renal function remained stable, whereas continuation of cyclosporine was accompanied by a rise in serum creatinine from 142 +/- 48 micromol/L to 157 +/- 62 micromol/L (p < 0.05 comparing both groups). Conversion to tacrolimus resulted in a sustained reduction in systolic and diastolic blood pressure, and a sustained improvement in the serum lipid profile, leading to a reduction in the Framingham risk score from 5.7 +/- 4.3 to 4.8 +/- 5.3 (p < 0.05). Finally, conversion to tacrolimus resulted in decreased scores for occurrence of and distress due to side-effects. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients is beneficial with respect to renal function, cardiovascular risk profile, and side-effects. Therefore, for most renal transplant patients tacrolimus will be the drug of choice when long-term treatment with a calcineurin inhibitor is indicated.  相似文献   
12.
13.
A 59-year-old man developed a lower respiratory tract infection 10 years after orthotopic cardiac transplantation. He did not respond to broad-spectrum antibiotic and antifungal treatment. Parainfluenza virus type 3 was the causative organism, and he was successfully treated with intravenous ribavirin and methylprednisolone.  相似文献   
14.
15.
The 16-18 year period is a crucial time for the personal and professional development of young people. Over the past ten years a range of educational innovations have been introduced which are having a profound effect on many in this age group including National Vocational Qualifications (NVQs) based on nationally agreed standards of professional competence and intended as occupational awards. More recently, General National Vocational Qualifications (GNVQs) have developed beyond the pilot stage, adding a broader vocational perspective and providing enhanced opportunities for progression to higher education. These have opened the door to new opportunities for progression to higher education for the 16 18 age group. The new qualifications are more easily identified through comparison with the corresponding and more traditional qualifications, as shown in table one. Traditionally, British universities have had a history of fairly high completion rates owing to stringent entry requirements and full funding for students. This is not the case in the vocational education system where access to GNVQ and NVQ programmes is facilitated through less rigid entry requirements, and, particularly in relation to GNVQs, the students tend to be school-leavers. In addition, the vocational awards are complex in terms of structure and make considerable demands on student autonomy. While the issue of student funding in vocational education is currently under review, students have not usually been funded through maintenance grants, though local education authorities have offered a small number of discretionary grants, usually to mature students.  相似文献   
16.
17.
In vitro human hepatocyte cultures are a key tool in the investigation of xenobiotic toxicity and metabolism. In most in vitro hepatocyte studies, the cells are allowed to adhere to an extracellular matrix, such as collagen. Unfortunately, the ability of freshly isolated hepatocytes to adhere to collagen varies from donor to donor. We used microarray analysis to determine what gene expression differences exist between hepatocytes in suspension and hepatocytes attached to collagen. Results from different donors showed a considerable difference in gene expression patterns between the two hepatocyte populations. In addition, we also compared the gene expression profiles of hepatocytes in culture with liver tissue. The results showed that both hepatocytes in suspension and hepatocytes attached to collagen display significant gene expression differences compared with liver tissue. Finally, we show that both populations of hepatocytes are responsive to dexamethasone and regulate some of the same genes. Overall, our results suggest that either significant gene expression changes occur in isolated hepatocytes or that suspended and attached cells represent different populations of hepatocytes found in intact livers.  相似文献   
18.
The authors examined the relationship of preinjury interpersonal resources and stressors to parental adaptation following pediatric traumatic brain injury (TBI) and orthopedic injury. Parents of children with severe TBI (n = 53), moderate TBI (n = 56), and orthopedic injuries (n = 80) were assessed soon after injury, 6 and 12 months after the initial evaluation, and at an extended follow-up with a mean of 4 years postinjury. General linear model analyses provide support for both main and moderating effects of stressors and resources on parental adjustment. Support from friends and spouse was associated with less psychological distress, whereas family and spouse stressors were associated with greater distress. The results also reveal a marked decline in injury-related stress over follow-up for families in the severe TBI group who reported a combination of high stressors and high resources. The decline suggests that interpersonal resources attenuated long-term family burden because of severe TBI. The findings are discussed in terms of their implications for intervention following TBI.  相似文献   
19.
Advances in genetics create increasing possibilities of diagnosing and preventing genetic disease. In most countries, the community is poorly informed about the role of genetic factors in human disease and about genetic testing and its social, emotional, and ethical implications. School education about genetics may improve this situation. Students are, of course, the adults of the future and the potential users of the new genetic tests. To gain further insight into the perception of genetic risk of adolescents and their perception of the new genetic techniques and as a starting point for setting up an adequate information campaign in Flanders, we assessed the opinions and beliefs of students with regard to health, genetic diseases, genetic risk, and genetic testing.

A standardised interview and questionnaire were administered within the scope of the two yearly medical check up of 166 fifth grade students. They were randomly selected from the group of all fifth grade high school students in seven different schools.

This paper focuses on the attitudes of adolescents towards obtaining genetic information, towards prenatal diagnosis and pregnancy termination. Adolescents in Flanders are interested in being informed about genetic risks and genetic diseases and in making use of prenatal diagnosis because they want to make informed reproductive decisions in the future and to be emotionally prepared for the birth of an affected child. They adopt a critical attitude towards pregnancy termination. The association between these attitudes and several relevant factors was investigated. This showed significant correlations between some attitudes and general health related prevention, perceived burden of genetic diseases, the importance of the value “own health”, the perceived role of society, and the regularity of religious practice. Some points for special attention were formulated with regard to information campaigns for adolescents.

  相似文献   
20.
Long range physical mapping within the p21 region of the X chromosomeIdentified a CpG rich Island approximately 180 kb centromericto the chronic granulomatous disease (CGD) locus. The segmentsadjacent to the CpG Island hybridized to discrete bands In DNAsof several species and when used to screen retinal cDNA librariesled to the Identification of cDNAs that detected a mRNA of 2.1kb in many tissues. Molecular characterization of correspondinggenomic clones of this novel human gene confirmed the originof the cDNA clones and Indicated a genomic structure with fiveexons spanning a total of 9 kb. The complete cDNA sequence revealedthat this gene contained a putative open reading frame of 116amino acids with a 3' untranslated region of 1.74 kb. The aminoacid sequence shows a high degree of similarity to the predictedproduct of the tctex-1 gene of the mouse t complex. As linkagestudies and patients with deletions have Implicated the Xp21region as containing the retInltls plgmentosa defect (RP3),the gene was assessed as a candidate disease gene In RP3 families.A single base pair polymorphism was Identified within the codingregion but no disease associated changes were found by singlestrand conformational polymorphism and sequencing analysis ofamplified exons of 20 RP patients. Analysis of a dinucleotiderepeat polymorphism within this gene In families affected withRP3 suggested refinement of the RP3 region.  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