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   74972篇
  免费   4222篇
  国内免费   169篇
耳鼻咽喉   917篇
儿科学   1752篇
妇产科学   1613篇
基础医学   9964篇
口腔科学   2747篇
临床医学   6171篇
内科学   18251篇
皮肤病学   1814篇
神经病学   6603篇
特种医学   1715篇
外国民族医学   1篇
外科学   9713篇
综合类   394篇
一般理论   47篇
预防医学   6701篇
眼科学   1467篇
药学   4945篇
中国医学   274篇
肿瘤学   4274篇
  2024年   60篇
  2023年   541篇
  2022年   317篇
  2021年   1304篇
  2020年   835篇
  2019年   1387篇
  2018年   2280篇
  2017年   1424篇
  2016年   1499篇
  2015年   2232篇
  2014年   2398篇
  2013年   3461篇
  2012年   6462篇
  2011年   6306篇
  2010年   2934篇
  2009年   2223篇
  2008年   5356篇
  2007年   5567篇
  2006年   5706篇
  2005年   5387篇
  2004年   4861篇
  2003年   4359篇
  2002年   4190篇
  2001年   1617篇
  2000年   2132篇
  1999年   1054篇
  1998年   283篇
  1997年   213篇
  1996年   200篇
  1995年   181篇
  1994年   150篇
  1993年   146篇
  1992年   162篇
  1991年   139篇
  1990年   110篇
  1989年   116篇
  1988年   93篇
  1987年   82篇
  1986年   96篇
  1985年   121篇
  1984年   130篇
  1983年   89篇
  1982年   109篇
  1981年   97篇
  1980年   104篇
  1979年   74篇
  1978年   68篇
  1977年   58篇
  1976年   58篇
  1974年   56篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
1.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
2.
3.
4.
5.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
6.

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   
7.
8.
9.
10.
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