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   2588篇
  免费   150篇
  国内免费   17篇
耳鼻咽喉   32篇
儿科学   108篇
妇产科学   111篇
基础医学   248篇
口腔科学   92篇
临床医学   238篇
内科学   524篇
皮肤病学   69篇
神经病学   208篇
特种医学   51篇
外科学   387篇
综合类   17篇
一般理论   3篇
预防医学   307篇
眼科学   59篇
药学   138篇
中国医学   3篇
肿瘤学   160篇
  2023年   15篇
  2022年   47篇
  2021年   80篇
  2020年   44篇
  2019年   76篇
  2018年   80篇
  2017年   55篇
  2016年   81篇
  2015年   90篇
  2014年   106篇
  2013年   136篇
  2012年   192篇
  2011年   202篇
  2010年   113篇
  2009年   111篇
  2008年   182篇
  2007年   177篇
  2006年   162篇
  2005年   151篇
  2004年   158篇
  2003年   94篇
  2002年   113篇
  2001年   53篇
  2000年   38篇
  1999年   34篇
  1998年   11篇
  1997年   16篇
  1996年   5篇
  1995年   5篇
  1994年   6篇
  1993年   4篇
  1992年   10篇
  1991年   15篇
  1990年   9篇
  1989年   7篇
  1988年   6篇
  1987年   8篇
  1986年   8篇
  1985年   6篇
  1983年   7篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1975年   4篇
  1974年   4篇
  1973年   2篇
  1972年   2篇
  1971年   11篇
  1969年   5篇
  1968年   2篇
排序方式: 共有2755条查询结果,搜索用时 640 毫秒
1.
2.
The World Health Report 2000 on health systems has raised concerns about its political biases, its methods and indicators, and its lack of reliable data. Tracing the origins of the Report, this article argues that it counteracts many of the concerns that gave rise to preparation of the Report in the first place. The mutually agreed-upon value-base, expressed in the Health for All strategy, has been largely abandoned. The Report includes contradictory messages, and many of its recommendations are not evidence-based. Furthermore, the ranking of countries according to their health systems' performance is not useful for health-policy-making, even if the methods and data could be improved. Because the member states and governing bodies of the WHO were not consulted during the production of the Report, the WHO secretariat has not received a mandate to change the value-base of the WHO's health policy or the aims of the Report. The WHO should return to its mandate as a normative intergovernmental U.N. agency on health.  相似文献   
3.
A role for decorin in cutaneous wound healing and angiogenesis   总被引:2,自引:0,他引:2  
Decorin is known to influence tissue tensile strength and cellular phenotype. Therefore, decorin is likely to have an impact on tissue repair, including cutaneous wound healing. In this study, cutaneous healing of both excisional and incisional full‐thickness dermal wounds was studied in decorin‐deficient (Dcn?/?) animals. A statistically significant delay in excisional wound healing in the Dcn?/? mice occurred at 4 and 10 days postwounding and, in incisional wounds at 4, 10, and 18 days when compared with wild‐type (Dcn?/?) controls. Fibrovascular invasion into polyvinylalcohol sponges was significantly increased by day 18 in Dcn?/? mice relative to Dcn+/+ mice. The 18‐day sponge implants in the Dcn?/? mice showed a marked accumulation of biglycan when compared with the corresponding implants in Dcn+/+ mice. Thus, regulated production of decorin may serve as an excellent therapeutic approach for modifying impaired wound healing and harmful foreign body reactions.  相似文献   
4.
Health has gained importance on the global agenda. It has become recognized in forums where it was once not addressed. In this article three issues are considered: global health policy actors, global health priorities and the means of addressing the identified health priorities. I argue that the arenas for global health policy-making have shifted from the public spheres towards arenas that include the transnational for-profit sector. Global health policy has become increasingly fragmented and verticalized. Infectious diseases have gained ground as global health priorities, while non-communicable diseases and the broader issues of health systems development have been neglected. Approaches to tackling the health problems are increasingly influenced by trade and industrial interests with the emphasis on technological solutions.  相似文献   
5.
Effects of endothelin-1 on epithelial ion transport in human airways   总被引:1,自引:0,他引:1  
Endothelin-1 (ET-1) exerts many biological effects in airways, including bronchoconstriction, airway mucus secretion, cell proliferation, and inflammation. We investigated the effect of ET-1 on Na absorption and Cl secretion in human bronchial epithelial cells. Addition of 10(-7) M ET-1 had no effect on the inhibition of the short circuit current (Isc) induced by amiloride, a Na channel blocker. Addition of 10(-7) M ET-1 to the apical bath in the presence of amiloride increased Isc in cultured human bronchial epithelial cells studied in Ussing chambers. No effect was observed when ET-1 was added to basolateral bath, indicating that the involved ET-1 receptors are likely present only in the apical membrane of the cells. Use of Cl-free solutions and bumetanide reduced the ET-1-induced increases in Isc, indicating that ET-1 stimulates Cl secretion. The ET-1-induced increase in Isc was prevented by exposure to the ETB receptor antagonist BQ-788 but not to the ETA receptor antagonist BQ-123. ET-1 did not raise intracellular Ca levels, but increased the intracellular concentration of cAMP. These findings indicate that ET-1 is a Cl secretagogue in human airways and acts presumably through apically located ETB receptors and activation of the cAMP pathway.  相似文献   
6.
An enzyme immunoassay (EIA) for serum antibodies to human immunodeficiency virus type 1 (HIV-1), based on the synthetic pentadecapeptide SGKLICT-TAVPWNAS, a segment of the transmembrane glycoprotein (gp41) of the virus, was developed and tested for sensitivity and specificity. Sera of 152 individuals at various stages of HIV-1 infection, including two prospectively and six retrospectively studied patients exposed to HIV-1 but seronegative on initial testing in whole-virus EIA and immunoblotting, were screened with the gp41 peptide antibody EIA. The reference population consisted of 1,000 healthy HIV-1 antibody-negative blood donors. In addition, five individuals with antibodies to HIV-2 were studied. Antibodies to the synthetic peptide were detected in 100% of those with asymptomatic infection. Only one patient with LAS failed to react in the peptide EIA. Patients with HIV-2 infection did not react in this test. The peptide antibodies appeared rapidly after infection, were detectable at the time when seroconversion was observed by immunoblotting, and preceded reactivity in whole-virus EIA. Sera of seven patients with verified HIV-1 infection did not react with gp41 in immunoblotting, although antibodies were readily detectable in the gp41 peptide EIA.  相似文献   
7.
Familial amyloidosis, Finnish type (FAF) (gelsolin-related amyloidosis) is an autosomal dominant form of systemic amyloidosis characterized by corneal lattice dystrophy and peripheral polyneuropathy. The accumulating protein in FAF consists of fragments of gelsolin, an actin-modulating protein. The gelsolin mutation G654A has been found in both Finnish and Japanese patients. To study the origin of the gelsolin mutation in these patients we performed haplotype analysis in 10 Finnish and 2 Japanese FAF families. Poymorphic DNA markers GSN, D9S103, AFMa061xd9, and AFMa139xb9 revealed a uniform disease haplotype in all the disease-associated chromosomes of the Finnish FAF families, which was different from the one observed in the Japanese families. The present results and the previously detected gelsolin mutation G654T in Czech and Danish FAF patients suggest that nucle otide 654 may represent a mutation hot spot in the gelsolin gene. The DNA markers studied here will be useful in future genealogical analyses of FAF. © 1995 Wiley-Liss, Inc.  相似文献   
8.
BACKGROUND: The aim of the European Sero-Epidemiology Network (ESEN2) is to harmonise the serological surveillance of vaccine-preventable diseases in Europe. OBJECTIVE: To allow comparison of antibody prevalence in different countries by standardising results into common units. STUDY DESIGN: For varicella zoster virus (VZV), a reference laboratory established a panel of 148 samples, characterised by indirect enzyme-immunoassay (ELISA), indirect immunofluorescence, and complement fixation test. Fifty-seven samples were also studied by the fluorescence antibody to membrane antigen test. The geometric mean of the antibody activity (GMAA) obtained from four ELISA determinations was used to characterise each sample of the panel as positive (GMAA: >100 mIU/ml), equivocal (GMAA: 50-100 mIU/ml) or negative (GMAA: <50 mIU/ml) for antibody to VZV (anti-VZV). Thirteen laboratories, using five different ELISA tests, tested the panel. RESULTS: Agreement with the reference laboratory was above 85% in all cases, and the R(2) values obtained from regression analysis of the quantitative results were always higher than 0.87. Finally, the regression equations could be used to convert national values into a common unitage. CONCLUSION: This study confirmed that results for anti-VZV obtained by different ELISA methods can be converted into common units, enabling the comparison of the seroprevalence profiles obtained in the participant countries.  相似文献   
9.
PSORS1, near HLA-C, is the major genetic determinant of psoriasis. We present genetic and structural evidence suggesting a major role for the HCR gene at the PSORS1 locus. Genotyping of 419 families from six populations revealed that coding single-nucleotide polymorphisms of HCR formed a conserved allele HCR*WWCC that associated highly significantly with psoriasis and with the HLA-Cw6 allele in all populations. Because of strong linkage disequilibrium between HLA-Cw6 and HCR*WWCC, the two genes could not be genetically distinguished by this sample size. However, the variant HCR allele was predicted to differ in secondary structure from the wild-type protein. HCR protein expression in lesional psoriatic skin differed considerably from that observed in normal skin. These results provide strong evidence for the HCR*WWCC allele as a major genetic determinant for psoriasis, probably by a mechanism impacting on keratinocyte proliferation.  相似文献   
10.
Iron deficiency anaemia is frequently observed in male adults and postmenopausal women due to chronic occult bleeding, usually from the gastrointestinal tract. Practically, as endoscopical investigation of the gastrointestinal system is an invasive procedure, iron replacement treatment was generally started without investigation of the underlying aetiology even in first-line health institutions. This study evaluates the role of endoscopy in the investigation of the aetiology of anaemia in 95 patients (51 males, 44 females), aged 64.9+/-12.5 years (range 50-90 years). All patients having iron deficiency anaemia were investigated by upper gastrointestinal endoscopy and colonoscopy. Upper and lower gastrointestinal pathologies were seen in 10 (10.6%) and 55 (57.8%) patients, respectively. However, no gastrointestinal lesion was found in 30 (31.6%) patients with iron deficiency anaemia. Out of the 95 patients, 16 (16.9%) had erosive gastritis, 15 (15.8%) duodenal ulcer, 8 (8.4%) gastric ulcer, 7 (7.3%) gastric tumours, 7 (7.3%) oesophagitis. 5 (5.4%) colon tumours, 3 (3.2%) haemorrhoids, 2 (2.1%) non-tropical sprue, 1 (1%) colonic polyp, and 1 (1%) colitis. In the majority of elderly patients with iron deficiency anaemia, upper gastrointestinal system disease was found. In 12 (12.7%) patients in the study group, malignancies were detected. In elderly patients with iron deficiency anaemia, the aetiology should be highlighted before giving iron supplementation.  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