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   12149篇
  免费   824篇
  国内免费   55篇
耳鼻咽喉   77篇
儿科学   369篇
妇产科学   349篇
基础医学   1707篇
口腔科学   189篇
临床医学   1448篇
内科学   2508篇
皮肤病学   271篇
神经病学   1366篇
特种医学   404篇
外科学   1035篇
综合类   103篇
一般理论   2篇
预防医学   1059篇
眼科学   362篇
药学   659篇
中国医学   26篇
肿瘤学   1094篇
  2024年   15篇
  2023年   134篇
  2022年   223篇
  2021年   457篇
  2020年   291篇
  2019年   421篇
  2018年   395篇
  2017年   315篇
  2016年   361篇
  2015年   372篇
  2014年   487篇
  2013年   696篇
  2012年   1009篇
  2011年   1024篇
  2010年   527篇
  2009年   438篇
  2008年   775篇
  2007年   803篇
  2006年   710篇
  2005年   604篇
  2004年   602篇
  2003年   540篇
  2002年   537篇
  2001年   75篇
  2000年   64篇
  1999年   99篇
  1998年   94篇
  1997年   68篇
  1996年   55篇
  1995年   47篇
  1994年   51篇
  1993年   46篇
  1992年   44篇
  1991年   51篇
  1990年   21篇
  1989年   34篇
  1988年   26篇
  1987年   32篇
  1985年   30篇
  1984年   33篇
  1983年   26篇
  1982年   32篇
  1981年   35篇
  1980年   36篇
  1979年   24篇
  1978年   27篇
  1977年   21篇
  1976年   20篇
  1975年   17篇
  1974年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
Geophagic soils from selected communities in Eastern Cape, South Africa were characterised to determine their properties and geohelminth content. The soils were coarse-textured with cation exchange capacity values ranging from 6.35 to 18.94?cmol (+)/kg. Quartz was the dominant mineral in the samples with SiO2, Al2O3, and Fe2O3(t) having the highest concentrations among major element oxides. The soil properties, mineralogical composition, and low amounts of particle binding substances may favour the survival of geohelminth ova in the soils. Seven of the samples contained at least one of the following geohelminths: Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and Strongyloides stercoralis. The presence of these geohelminths in the soils was attributed to agricultural and sanitary practices inherent in the communities and the soil properties. Communities need to be sensitised on the importance of safe sanitary and animal husbandry practices to reduce the prevalence of helminth infection among geophagists.  相似文献   
132.
133.
134.
135.
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive, metastatic disease with limited treatment options. Factors contributing to the metastatic predisposition and therapy resistance in pancreatic cancer are not well understood. Here, we used a mouse model of KRAS-driven pancreatic carcinogenesis to define distinct subtypes of PDAC metastasis: epithelial, mesenchymal and quasi-mesenchymal. We examined pro-survival signals in these cells and the therapeutic response differences between them. Our data indicate that the initiation and maintenance of the transformed state are separable, and that KRAS dependency is not a fundamental constant of KRAS-initiated tumors. Moreover, some cancer cells can shuttle between the KRAS dependent (drug-sensitive) and independent (drug-tolerant) states and thus escape extinction. We further demonstrate that inhibition of KRAS signaling alone via co-targeting the MAPK and PI3K pathways fails to induce extensive tumor cell death and, therefore, has limited efficacy against PDAC. However, the addition of histone deacetylase (HDAC) inhibitors greatly improves outcomes, reduces the self-renewal of cancer cells, and blocks cancer metastasis in vivo. Our results suggest that targeting HDACs in combination with KRAS or its effector pathways provides an effective strategy for the treatment of PDAC.  相似文献   
136.
137.
Community-based interventions (CBI) have been targeted as a potential means of tackling cardiovascular disease in women. However, there have been mixed results in terms of their impact on health, with at least some of this being attributed to high attrition rates. This study explores factors that may be contributing to the low retention of women in cardiovascular CBIs. In 2009, Sister to Sister, a national organization that sponsors community health fairs, provided free cardiovascular health screenings for a total of 9,443 women nationwide. All participants were invited to enroll in a 1 year, survey-based observational study to assess the effectiveness of these community health screenings. Of these 9,443 women, 5.9 % actively participated in the follow-up study. Participants were more likely to have health insurance (75.5 vs. 65.3 %, p < 0.001), have an annual income above 75,000 dollars (26.7 vs. 19.7 %, p < 0.001), and identify themselves as white (50.0 vs. 31.5 %, p < 0.001). They were also more likely to have hypertension (32.1 vs. 27.4 %, p = 0.018) and metabolic syndrome (35.7 vs. 20.4 %, p < 0.001). Our results suggest that white, affluent women with health insurance and cardiovascular risk factors are more likely to engage in CBIs that require longitudinal assessment. This study gives insight into the demographics, socioeconomic status, and cardiovascular comorbidities of women who participate in cardiovascular CBIs. The results may prove to be useful in understanding the biopsychosocial barriers to participation in CBIs in order to develop more effective interventions in the future.  相似文献   
138.
139.
140.
Hydatidosis is a parasitic infection caused by the tapeworm larva of Echinococcus spp. Its relevance lies in its wide distribution, great number of clinical cases and outstanding morbility. Hydatid infection of the orbit comprises far less than 1% of the total incidence. This is a case of a patient from Argentina complaining of a two-week evolution proptosis of the right eye. A microscopic examination revealed the presence of protoscolices of Echinococcus spp. in the fluid obtained during the surgical proceedings. The patient was treated with oral albendazole. To our knowledge, this is the first case of occular hydatidosis diagnosed in the city of Buenos Aires, Argentina.  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