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   2790篇
  免费   188篇
  国内免费   4篇
耳鼻咽喉   40篇
儿科学   73篇
妇产科学   54篇
基础医学   338篇
口腔科学   91篇
临床医学   430篇
内科学   818篇
皮肤病学   38篇
神经病学   140篇
特种医学   94篇
外国民族医学   2篇
外科学   307篇
综合类   39篇
一般理论   5篇
预防医学   252篇
眼科学   23篇
药学   93篇
肿瘤学   145篇
  2021年   31篇
  2020年   19篇
  2019年   35篇
  2018年   49篇
  2017年   31篇
  2016年   37篇
  2015年   36篇
  2014年   51篇
  2013年   68篇
  2012年   102篇
  2011年   134篇
  2010年   84篇
  2009年   83篇
  2008年   133篇
  2007年   159篇
  2006年   136篇
  2005年   128篇
  2004年   124篇
  2003年   107篇
  2002年   111篇
  2001年   68篇
  2000年   73篇
  1999年   67篇
  1998年   35篇
  1997年   26篇
  1996年   24篇
  1995年   22篇
  1994年   20篇
  1992年   75篇
  1991年   50篇
  1990年   64篇
  1989年   49篇
  1988年   51篇
  1987年   62篇
  1986年   41篇
  1985年   53篇
  1984年   41篇
  1983年   49篇
  1982年   23篇
  1980年   28篇
  1979年   30篇
  1978年   29篇
  1977年   33篇
  1976年   22篇
  1975年   24篇
  1974年   25篇
  1973年   18篇
  1972年   25篇
  1971年   28篇
  1970年   22篇
排序方式: 共有2982条查询结果,搜索用时 15 毫秒
71.
Multiple myeloma management has undergone profound changes in the past thanks to advances in our understanding of the disease biology and improvements in treatment and supportive care approaches. This article presents recommendations of the European Myeloma Network for newly diagnosed patients based on the GRADE system for level of evidence. All patients with symptomatic disease should undergo risk stratification to classify patients for International Staging System stage (level of evidence: 1A) and for cytogenetically defined high- versus standard-risk groups (2B). Novel-agent-based induction and up-front autologous stem cell transplantation in medically fit patients remains the standard of care (1A). Induction therapy should include a triple combination of bortezomib, with either adriamycin or thalidomide and dexamethasone (1A), or with cyclophosphamide and dexamethasone (2B). Currently, allogeneic stem cell transplantation may be considered for young patients with high-risk disease and preferably in the context of a clinical trial (2B). Thalidomide (1B) or lenalidomide (1A) maintenance increases progression-free survival and possibly overall survival (2B). Bortezomib-based regimens are a valuable consolidation option, especially for patients who failed excellent response after autologous stem cell transplantation (2A). Bortezomib-melphalan-prednisone or melphalan-prednisone-thalidomide are the standards of care for transplant-ineligible patients (1A). Melphalan-prednisone-lenalidomide with lenalidomide maintenance increases progression-free survival, but overall survival data are needed. New data from the phase III study (MM-020/IFM 07-01) of lenalidomide-low-dose dexamethasone reached its primary end point of a statistically significant improvement in progression-free survival as compared to melphalan-prednisone-thalidomide and provides further evidence for the efficacy of lenalidomide-low-dose dexamethasone in transplant-ineligible patients (2B).  相似文献   
72.
Changes in head position and posture are detected by the vestibular system and are normally followed by rapid modifications in blood pressure. These compensatory adjustments, which allow humans to stand up without fainting, are mediated by integration of vestibular system pathways with blood pressure control centers in the ventrolateral medulla. Orthostatic hypotension can reflect altered activity of this neural circuitry. Vestibular sensory input to the vestibulo‐sympathetic pathway terminates on cells in the vestibular nuclear complex, which in turn project to brainstem sites involved in the regulation of cardiovascular activity, including the rostral and caudal ventrolateral medullary regions (RVLM and CVLM, respectively). In the present study, sinusoidal galvanic vestibular stimulation was used to activate this pathway, and activated neurons were identified through detection of c‐Fos protein. The retrograde tracer Fluoro‐Gold was injected into the RVLM or CVLM of these animals, and immunofluorescence studies of vestibular neurons were conducted to visualize c‐Fos protein and Fluoro‐Gold concomitantly. We observed activated projection neurons of the vestibulo‐sympathetic reflex pathway in the caudal half of the spinal, medial, and parvocellular medial vestibular nuclei. Approximately two‐thirds of the cells were ipsilateral to Fluoro‐Gold injection sites in both the RVLM and CVLM, and the remainder were contralateral. As a group, cells projecting to the RVLM were located slightly rostral to those with terminals in the CVLM. Individual activated projection neurons were multipolar, globular, or fusiform in shape. This study provides the first direct demonstration of the central vestibular neurons that mediate the vestibulo‐sympathetic reflex. J. Comp. Neurol. 522:2053–2074, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   
73.
Most exercise testing is performed in adults with known or suspected ischemic heart disease. In the last few years cardiac imaging techniques have been applied in this field, improving the information obtained with the procedure. However, the exceptions to this rule are emerging rapidly not only in healthy people (asymptomatic individuals, athletes, handicapped people) but also in cardiac patients (advanced congestive heart failure, hypertension, rhythm disorders, congenital heart disease, etc.). All the-se issues justify the need for a multidisciplinary consensus document in Spain.This paper reviews and updates the methodological aspects of the stress test, including those related to oxygen consumption measurements. The main aim of this review was to determine the role of exercise testing in the evaluation of ischemic heart disease as well as the applications of imaging stress testing. The usefulness of this test in other non-ischemic cardiac disorders and in selected subsets of healthy people is also reviewed.  相似文献   
74.
Objective. To compare the expression of cathepsin L, cathepsin D, and collagenase messenger RNA (mRNA) in synovial specimens from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Methods. The expression of cathepsins L and D as well as collagenase mRNA in synovial tissues from 8 patients with RA, 6 patients with OA, and 2 patients with noninflamed joints was evaluated using in situ hybridization with digoxigenin-labeled RNA probes. Results. Both RA and OA synovial tissue expressed cathepsins L and D as well as collagenase mRNA. The expression of the cathepsins was markedly higher in interstitial regions and, to some extent, in perivascular infiltrates of RA synovial tissue compared with OA specimens. Conclusion. Cathepsins L and D mRNA are expressed differently in RA and OA synovial tissues, supporting the concept that these enzymes may contribute to the influx of mononuclear cells into RA synovium. Moreover, the data reveal that the expression of collagenase and cathepsins in RA and OA synovial lining is otherwise largely similar, and suggest that the adhesion of synovial cells to cartilage mediates the invasive destructive process in RA.  相似文献   
75.
Over the course of 17 years, 7 women have had heart disease either during the last three months of pregnancy or during the first three months post-partum, which appear to be associated with their pregnancy. Enquiries made throughout the country and relating to the last decade have yielded 11 additional cases so far unpublished. The clinical features of these cases do not differ from those of other non-obstructive cardiomyopathies occurring other than in pregnancy. The prognosis depends essentially on the factor of cardiac volume during the first few months of the disorder: if significant cardiomegaly persists, death will follow in one case out of two. There exists the problem of the criteria for making a diagnosis of myocardial disease of pregnancy. It should be emphasised that only 4 of the 18 cases were different from the usual cases of myocardial disease, in that they progressed to recovery which is unusual in this condition. One case was particularly illustrative of this, as clinical cure was followed by a relapse at subsequent pregnancy. Because the pregnancy itself seems to be the cause in such a tiny number of cases, a new hypothesis seems right; this is that pregnancy does no more than aggravate an associated or already existent myocardial disorder.  相似文献   
76.

Objective

The LCE3C_LCE3B‐del variant is associated with psoriasis and rheumatoid arthritis. Its role in psoriatic arthritis (PsA) is unclear, however, as shown by 3 recent studies with contradictory results. In order to investigate whether LCE3C_LCE3B‐del constitutes a risk factor for PsA susceptibility, we first tested this variant in patients with PsA from Spanish and Italian populations and then performed a meta‐analysis including the previous case–control studies.

Methods

We genotyped LCE3C_LCE3B‐del and its tag single‐nucleotide polymorphism (SNP), rs4112788, in an original discovery cohort of 424 Italian patients with PsA and 450 unaffected control subjects. A Spanish replication cohort consisting of 225 patients with PsA and 469 control subjects was also genotyped. A meta‐analysis considering 7,758 control subjects and 2,325 patients with PsA was also performed.

Results

We observed a significant association between PsA and the LCE3C_LCE3B‐del tag SNP in the Italian and Spanish cohorts, with an overall corrected P value of 0.00019 and a corresponding odds ratio of 1.35 (95% confidence interval 1.14–1.59). Stratified analyses by subphenotype indicated a stronger association for patients with oligoarticular disease. Meta‐analysis including data from all previous published studies confirmed an association of PsA with the LCE3C_LCE3B‐del tag SNP.

Conclusion

LCE3C_LCE3B‐del is a susceptibility factor for PsA, confirming the existence of a shared risk factor involving the epidermal skin barrier in autoimmune disorders.
  相似文献   
77.
The activities of ciprofloxacin and norfloxacin against 100 mycobacteria isolates were studied in vitro by the 1% standard proportion method. Ciprofloxacin was more active against M. tuberculosis and M. fortuitum with MICs of 1.0 and 0.25 microgram/ml, respectively, against 90% of isolates; norfloxacin had MICs of 8.0 and 2.0 micrograms/ml, respectively, against 90% of isolates.  相似文献   
78.
79.
OBJECTIVE: To determine zidovudine pharmacokinetics and tolerance in premature human human immunodeficiency virus-exposed infants. STUDY DESIGN: Pediatric AIDS Clinical Trials Group Study 331 was a multicentered prospective, open-label study of the use of zidovudine in premature infants. Thirty-eight infants <35 weeks' gestational age (GA) were studied while receiving zidovudine 1.5 mg/kg every 12 hours until 2 weeks of age, then 2.0 mg/kg every 8 hours until 6 weeks of age. Population pharmacokinetics were evaluated at 1, 2, and 4 weeks' postnatal age; zidovudine doses were adjusted to maintain troughs <3 microM. RESULTS: Zidovudine clearance was lower than reported in term infants at similar postnatal ages. Nine premature infants required dose reduction because of high levels (7/19 <30 weeks' and 2/19 >/=30 weeks' GA). Postnatal age, GA, serum creatinine, and furosemide use independently predicted zidovudine clearance. Zidovudine was generally well tolerated in this high-risk population. CONCLUSIONS: Zidovudine clearance is greatly reduced in premature infants. We recommend the following zidovudine dosing schedule in this population: 1.5 mg/kg (intravenous) or 2.0 mg/kg (oral) every 12 hours increased to every 8 hours at 2 weeks of age (>/=30 weeks' GA) or at 4 weeks (<30 weeks' GA).  相似文献   
80.
Rheumatoid arthritis (RA) has been thought to be largely a T-cell-mediated disease. To evaluate the role of T-cell-independent pathways in RA, we examined the interaction between isolated RA synovial fibroblasts and normal human cartilage engrafted into SCID mice in the absence of T cells and other human cells. The expression of cartilage-de grading enzymes and adhesion molecules was examined by immunohistochemistry and in situ hybridization techniques. The RA synovial fibroblasts invaded the cartilage and kept their transformed appearing cellular shape. They expressed VCAM-1 and produced the cathepsins L and B at the site of invasion. We conclude that RA synovial fibroblasts maintain their invasive and destructive behavior over longer periods of time in the absence of human T cells, indicating that T-cell-independent pathways play a significant role in rheumatoid joint destruction.  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