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   57072篇
  免费   4574篇
  国内免费   242篇
耳鼻咽喉   548篇
儿科学   1822篇
妇产科学   1238篇
基础医学   6730篇
口腔科学   1004篇
临床医学   5512篇
内科学   11709篇
皮肤病学   1253篇
神经病学   4685篇
特种医学   2080篇
外国民族医学   1篇
外科学   8705篇
综合类   1245篇
一般理论   74篇
预防医学   4315篇
眼科学   2142篇
药学   4101篇
  1篇
中国医学   147篇
肿瘤学   4576篇
  2023年   273篇
  2022年   423篇
  2021年   1087篇
  2020年   697篇
  2019年   1036篇
  2018年   1222篇
  2017年   927篇
  2016年   1051篇
  2015年   1193篇
  2014年   1728篇
  2013年   2236篇
  2012年   3483篇
  2011年   3609篇
  2010年   2082篇
  2009年   1844篇
  2008年   3289篇
  2007年   3303篇
  2006年   3185篇
  2005年   3166篇
  2004年   3148篇
  2003年   2857篇
  2002年   2692篇
  2001年   1539篇
  2000年   1342篇
  1999年   1230篇
  1998年   670篇
  1997年   573篇
  1996年   521篇
  1995年   512篇
  1994年   443篇
  1993年   407篇
  1992年   798篇
  1991年   732篇
  1990年   669篇
  1989年   643篇
  1988年   575篇
  1987年   536篇
  1986年   527篇
  1985年   552篇
  1984年   441篇
  1983年   430篇
  1982年   391篇
  1981年   366篇
  1980年   329篇
  1979年   328篇
  1978年   275篇
  1977年   275篇
  1976年   185篇
  1975年   193篇
  1974年   228篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
In the present review, we updated current information on the chemistry, contents, and anticancer properties of matrine (MT), oxymatrine (OMT), and compound Kushen injection (CKI). The anticancer properties were focused on lung, breast, and liver cancer cells because they are most susceptible. Sources of information were from Google, Google Scholar, PubMed, PubMed Central, Science Direct, PubChem, J-Stage, Directory of Open Access Journals (DOAJ), and China National Knowledge Infrastructure (CNKI). Reference was also made on botanical websites, such as Flora of China and World Flora Online. MT and OMT are dominant quinolizidine alkaloids from the roots of Sophora flavescens (Kushen) of the family Fabaceae. Against lung, breast, and liver cancer cells, MT and OMT inhibit cell proliferation; induce cell cycle arrest, apoptosis, and autophagy; restrict angiogenesis; and inhibit cell metastasis, invasion, and migration. The processes involve various molecular targets and signaling pathways. CKI is a traditional Chinese medicine (TCM) composed of root extracts of S. flavescens and Smilax glabra (Baituling) of the family Smilacaceae. With MT and OMT as major components, CKI has been approved for the treatment of cancer in China more than 20 years ago. In recent years, systematic reviews and meta-analysis have been undertaken to evaluate the anticancer effects of CKI. When CKI is used alone and in combination with chemotherapy of western medicine, there is much to be learned concerning their interactions besides their individual and integrated efficacy. Some perspectives of MT, OMT, and CKI are discussed, and their suggestions for future research are provided.  相似文献   
14.
ObjectiveTo evaluate changes in insurance status among emergency department (ED) patients presenting in the two years immediately before and after full implementation of the Affordable Care Act (ACA).MethodsWe evaluated National Hospital Ambulatory Medical Care Survey (NHAMCS) Emergency Department public use data for 2012–2015, categorizing patients as having any insurance (private; Medicare; Medicaid; workers' compensation) or no insurance. We compared the pre- and post-ACA frequency of insurance coverage—overall and within the older (≥65), working-age (18–64) and pediatric (<18) subpopulations—using unadjusted odds ratios with 95% confidence intervals. We also conducted a difference-in-differences analysis comparing the change in insurance coverage among working-age patients with that observed for older Medicare-eligible patients, while controlling for sex, race and underlying temporal trends.ResultsOverall, the proportion of ED patients with any insurance did not significantly change from 2012 to 2013 to 2014–2015 (74.2% vs 77.7%) but the proportion of working-age adult patients with at least one form of insurance increased significantly, from 66.0% to 71.8% (OR 1.31, CI: 1.13–1.52). The difference-in-differences analysis confirmed the change in insurance coverage among working-age adults was greater than that seen in the reference population of Medicare-eligible adults (AOR 1.70, CI: 1.29–2.23). The increase was almost entirely attributable to increased Medicaid coverage.ConclusionIn the first two years following full implementation of the ACA, there was a significant increase in the proportion of working-age adult ED patients who had at least one form of health insurance. The increase appeared primarily associated with expansion of Medicaid.  相似文献   
15.
The porcine circovirus type 2 (PCV2) is a swine infectious viral pathogen of great significance in global swine herds. It was recently detected at another Province of South Africa sequel to the first detection of North American‐like strain (PCV2a) at Gauteng about two decades ago, but there is a dearth of information about the genomic features and diversity of the viral strains in circulation within the country and the entire sub‐Saharan Africa region. To date, only one complete genome of the virus from South Africa is available on global data base. This current effort is therefore geared towards the full‐genome characterization of the circulating PCV2 strains in the pigs of Eastern Cape Province. With the use of conventional polymerase chain reaction method, fifteen complete PCV2 genomes were successfully amplified, sequenced and assembled from field samples obtained from non‐vaccinated pigs in the region. Neighbor Joining and Maximum Likelihood phylogenetic analyses of the ORF2 gene and full genomes unanimously showed that most of the assembled genomes (11) belong to genotype PCV2b. Furthermore, three of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (i.e. PCV2d) strains from the USA, China and South Korea. The last sequence, however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2‐IM2), recently identified in a global PCV2 strains phylogenetic analysis. This study reports the first complete genome sequences of PCV2b, PCV2d and PCV2‐IM2 in pigs from South Africa, and it gives a possible insight into the genetic characteristics and variability of the viral strains presently in circulation within the country. It further emphasizes the need for more stringent measures in curtailing the introduction and spread of transboundary swine pathogens in the country and entire Southern African region.  相似文献   
16.

Objective

A rapid and worrying emergence of vancomycin-resistant enterococci (VRE) gut colonization is occurring worldwide and may be responsible for outbreaks, especially in healthcare facilities. While no efficient decolonization strategies are recommended, we assessed fecal microbiota transplantation (FMT) to eradicate VRE colonization.

Patients and method

Our main objective was to measure the impact of FMT on decolonization of VRE carriers, confirmed by at least two consecutive negative rectal swabs at one-week interval during a 3-month follow-up period. Patients received no antibiotic prior to the FMT.

Results

After a month only three patients remained colonized with VRE. Decolonization was associated with 87.5% (n = 7) of success after three months as only one patient remained colonized.

Conclusion

Our first results confirm that the FMT seems to be safe, with an impact on VRE colonization over time that may help control outbreaks.  相似文献   
17.
18.
19.
20.
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