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   233683篇
  免费   11577篇
  国内免费   397篇
耳鼻咽喉   3050篇
儿科学   7277篇
妇产科学   4756篇
基础医学   33733篇
口腔科学   5323篇
临床医学   18484篇
内科学   51732篇
皮肤病学   6270篇
神经病学   20908篇
特种医学   7003篇
外国民族医学   101篇
外科学   29036篇
综合类   982篇
一般理论   62篇
预防医学   21266篇
眼科学   4553篇
药学   16411篇
中国医学   698篇
肿瘤学   14012篇
  2023年   1242篇
  2022年   873篇
  2021年   3465篇
  2020年   2051篇
  2019年   3894篇
  2018年   7435篇
  2017年   4872篇
  2016年   4863篇
  2015年   5439篇
  2014年   5685篇
  2013年   9182篇
  2012年   15979篇
  2011年   15959篇
  2010年   7953篇
  2009年   5952篇
  2008年   13710篇
  2007年   14681篇
  2006年   13512篇
  2005年   13371篇
  2004年   12536篇
  2003年   11445篇
  2002年   10837篇
  2001年   6130篇
  2000年   6213篇
  1999年   5548篇
  1998年   942篇
  1997年   783篇
  1996年   750篇
  1992年   3219篇
  1991年   2874篇
  1990年   2742篇
  1989年   2508篇
  1988年   2372篇
  1987年   2209篇
  1986年   2097篇
  1985年   1906篇
  1984年   1405篇
  1983年   1198篇
  1982年   680篇
  1979年   1211篇
  1978年   850篇
  1977年   796篇
  1975年   802篇
  1974年   987篇
  1973年   998篇
  1972年   940篇
  1971年   927篇
  1970年   861篇
  1969年   905篇
  1968年   788篇
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
71.
72.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
73.

Objective

To discover the experiences of end-of-life patients attended by the emergency services, through the discourse of the family caregivers who accompanied the family member in this care transit.

Method

A qualitative approach study, based on the paradigm of hermeneutical phenomenology. In total, 81 family caregivers participated. The techniques used were the in-depth interview and the discussion group, with a total of 5 discussion groups and 41 interviews. The period of data collection was carried out between January 2013 and June 2014.

Results

In the network of discourses obtained with respect to “Urgent Care”, all the codes were grouped in relation to a single argumentative line: deficiencies in urgent care. Among them, we found different dimensions that are established depending on the different times of care, or the different determinant aspects of these deficiencies: disorganization of the care received, lack of experience of the professionals in emergencies, application of general protocols in the emergency services, inadequate care in the treatment received, delays in emergency care.

Conclusions

In general, we highlight the dissatisfaction of the family members with respect to the care received from the emergency services. The needs of these types of situation are not covered from these services and are of low quality. Therefore, it is necessary to reorient the care protocols for these patients.  相似文献   
74.
75.
76.
77.
78.
79.
80.
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