首页 | 官方网站   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   43215篇
  免费   4712篇
  国内免费   869篇
医药卫生   48796篇
  2024年   58篇
  2023年   970篇
  2022年   927篇
  2021年   1801篇
  2020年   1797篇
  2019年   1765篇
  2018年   1745篇
  2017年   1679篇
  2016年   1541篇
  2015年   1370篇
  2014年   3174篇
  2013年   3248篇
  2012年   2557篇
  2011年   2717篇
  2010年   2090篇
  2009年   2006篇
  2008年   2273篇
  2007年   2330篇
  2006年   2086篇
  2005年   1756篇
  2004年   1430篇
  2003年   1367篇
  2002年   1053篇
  2001年   989篇
  2000年   798篇
  1999年   681篇
  1998年   497篇
  1997年   520篇
  1996年   369篇
  1995年   420篇
  1994年   365篇
  1993年   308篇
  1992年   299篇
  1991年   266篇
  1990年   225篇
  1989年   204篇
  1988年   199篇
  1987年   163篇
  1986年   127篇
  1985年   117篇
  1984年   101篇
  1983年   68篇
  1982年   67篇
  1981年   61篇
  1980年   59篇
  1979年   34篇
  1978年   29篇
  1977年   27篇
  1976年   18篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
Demographic situation, changes in the role of women in society and growing demand for long-term care (LTC) of older people have challenged the ability to meet the growing LTC needs in most developed countries. In countries where responsibility for LTC is still largely laid on families, it is, however, even more critical and calls for improvements in formal LTC systems. More intensive stakeholder collaboration in LTC policy development, organising and delivery are of primary importance in improving LTC systems. Such collaboration, however, is not always successful; thus, it is critical to understand what makes it effective and efficient. In this paper, we specifically look into multistakeholder collaboration in LTC in Lithuania, one of the fastest ageing countries in the EU, with the demand for LTC services growing fast and exceeding the supply despite rising business and NGO engagement. To determine facilitators of such collaboration, we build on the data obtained through eight focus group discussions with all key stakeholder representatives (LTC policymakers, organisers and service providers [public, private and NGOs], 54 participants in total). Our findings indicate that in addition to national and organisational level facilitators studied in prior research, there are important individual level factors, such as meaningfulness at work, concern and care for others, possibility for personal growth and development, satisfaction with supervision, a sense of belonging and role clarity. On the other hand, our results show that collaboration is constrained by a shortage of human resources, increased workload caused by growing LTC demand, bureaucratic requirements, legal restrictions, lack of awareness of LTC service availability among elder persons, and prevailing social norms and attitudes to institutionalised care. Interestingly, a lack of financial resources is not perceived as a major constraint.  相似文献   
3.
4.
This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.  相似文献   

5.
6.
7.
Abstract

Endometriosis is one of the most common gynecological diseases and a major cause of pain and infertility. It is influenced by genetic, epigenetic, and environmental factors. Recently, genome-wide association studies have revealed a strong association between IL1A single nucleotide polymorphisms (SNPs) and increased risk of endometriosis in Japanese women. The aim of the present study was to evaluate the association of three IL1A SNPs, rs17561, rs1304037, and rs2856836 with the risk of endometriosis in Iranian population. Totally, 105 women with diagnosis of endometriosis and 102 healthy women as control group were included. Three SNPs of the IL1A, rs17561?G/T, rs1304037 A/G, and rs2856836 T/C, were genotyped by PCR and RFLP. The rs2856836?TC genotype was significantly higher (p?=?.002; OR?=?3.1, 95% CI: 1.5–6.5) in the patients (28.1%) than the control group (12.7%). The rs2856836?CC genotype was significantly higher (p?=?.047; OR?=?2.3, 95% CI: 1.0–5.3) in the patients (17.5%) than the control group (10.8%). The rs2856836 C allele was significantly higher (p?=?.001; OR?=?2.2, 95% CI: 1.4–3.6) in the patients (31.6%) than the control group (17.2%). The IL1A rs2856836 T/C SNP was associated with susceptibility to endometriosis and the rs2856836 C allele may increase the risk of endometriosis in Iranian women.  相似文献   
8.
9.
BackgroundMetabolic syndrome (MetS) is related to the increased risk of major cardiovascular diseases (CVD). The link between high serum total bilirubin (TBL) is cross-sectionally related to MetS and its components. However, whether serum TBL predicts incidence of MetS and its components remains inconclusive.MethodsThe present study included 893 women aged 70 ± 9 years from a rural village. We examined the relationship between serum TBL and MetS based on the modified criteria of the National Cholesterol Education Program's Adult Treatment Panel (NCEP-ATP) III report in a cross-sectional (N = 893) and cohort (N = 288) data.ResultsIn the cross-sectional study, serum TBL (β = 0.536, p < 0.001) as well as age, alcohol consumption, exercise habits, history of CVD, SUA, GGT, and ALT was significantly and dependently associated with number of MetS components, but in the cohort study serum TBL was not associated with number of MetS components. Compared with the 1st tertile of serum TBL (0.20–0.55 mg/dL), multivariate-adjusted odds ratio (95% confidence interval) for the 2nd -3rd tertiles of serum TBL (0.54–2.00 mg/dL) was 0.70 (0.51–0.95) in the cross-sectional study and 0.41 (0.21–0.81) in the cohort study.ConclusionsOur data demonstrated an independently negative association between serum TBL and MetS in Japanese community-dwelling women.  相似文献   
10.
《Vaccine》2020,38(3):570-577
IntroductionPediatric pneumococcal pneumonia complicated by parapneumonic pleural effusion/empyema (PPE/PE) remains a major concern despite general immunization with pneumococcal conjugate vaccines (PCVs).MethodsIn a nationwide pediatric hospital surveillance study in Germany we identified 584 children <18 years of age with bacteriologically confirmed PPE/PE from October 2010 to June 2018. Streptococcus pneumoniae was identified by culture and/or PCR of blood samples and/or pleural fluid and serotyped.ResultsS. pneumoniae was identified in 256 of 584 (43.8%) children by culture (n = 122) and/or PCR (n = 207). The following pneumococcal serotypes were detected in 114 children: serotype 3 (42.1%), 1 (25.4%), 7F (12.3%), 19A (7.9%), other PCV13 serotypes (4.4%) and non-PCV13 serotypes (7.9%). Between October 2010 and June 2014 serotype 1 (38.1%) and serotype 3 (25.4%) were most prevalent, whereas between July 2014 and June 2018 serotype 3 (62.7%) and non-PCV13 serotypes (15.7%) were dominant. Compared to children with other pneumococcal serotypes, children with serotype 3 associated PPE/PE were younger (median 3.2 years [IQR 2.1–4.3 years] vs. median 5.6 years [IQR 3.8–8.2 years]; p < 0.001) and more frequently admitted to intensive care (43 [89.6%] vs. 48 [73.8%]; p = 0.04). Seventy-six of 114 (66.7%) children with pneumococcal PPE/PE had been vaccinated with pneumococcal vaccines. Thirty-nine of 76 (51.3%) had received a vaccine covering the serotype detected. Thirty of these 39 breakthrough cases were age-appropriately vaccinated with PCV13 and considered vaccine failures, including 26 children with serotype 3, three children with serotype 19A and one child with serotype 1.ConclusionFollowing the introduction of PCV13 in general childhood vaccination we observed a strong emergence of serotype 3 associated PPE/PE in the German pediatric population, including a considerable number of younger children with serotype 3 vaccine breakthrough cases and failures. Future PCVs should not only cover newly emerging serotypes, but also include a more effective component against serotype 3.  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-23

京公网安备 11010802026262号