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   934篇
  免费   73篇
耳鼻咽喉   10篇
儿科学   35篇
妇产科学   26篇
基础医学   104篇
口腔科学   17篇
临床医学   91篇
内科学   191篇
皮肤病学   20篇
神经病学   87篇
特种医学   7篇
外科学   191篇
综合类   14篇
预防医学   119篇
眼科学   12篇
药学   33篇
中国医学   4篇
肿瘤学   46篇
  2023年   5篇
  2022年   11篇
  2021年   17篇
  2020年   25篇
  2019年   30篇
  2018年   37篇
  2017年   26篇
  2016年   24篇
  2015年   25篇
  2014年   17篇
  2013年   34篇
  2012年   54篇
  2011年   61篇
  2010年   29篇
  2009年   33篇
  2008年   46篇
  2007年   43篇
  2006年   61篇
  2005年   70篇
  2004年   41篇
  2003年   52篇
  2002年   42篇
  2001年   29篇
  2000年   30篇
  1999年   26篇
  1998年   4篇
  1997年   4篇
  1996年   4篇
  1994年   4篇
  1993年   3篇
  1992年   16篇
  1991年   12篇
  1990年   10篇
  1989年   7篇
  1988年   5篇
  1987年   10篇
  1986年   5篇
  1985年   7篇
  1984年   2篇
  1983年   4篇
  1982年   2篇
  1980年   4篇
  1979年   4篇
  1978年   5篇
  1974年   5篇
  1973年   3篇
  1972年   2篇
  1971年   3篇
  1970年   2篇
  1966年   3篇
排序方式: 共有1007条查询结果,搜索用时 296 毫秒
1.
2.
3.
Summary We have studied the characteristics of arthritis present in 32 patients with Behçet's disease (BD), and how this arthritis is related to the HLA markers class I. 84% of the patients presented arthritis, the most common being monoarthritis as the initial presentation, and oligoarthritis in subsequent episodes. In 63% of the cases, the development was in episodes of acute/subacute arthritis. We found statistically significant association between antigens B-5 and B-51, and the group with BD, with a relative risk of 3.89 and 4.71 respectively. The attempt to relate markers B-5, B-51 and B-27 to the presence of arthritis as well as to its manifestation and further development was not conclusive.  相似文献   
4.
Aortic stent graft infection is rare and there are no reported cases of seeded peripheral mycotic aneurysms complicating this condition. We describe the case of a 54 year old man who developed a late stent graft infection at three years, resulting in the peripheral seeding of three mycotic aneurysms with two incidents of rupture. He was successfully treated with extra-anatomic bypass of the aorta and both surgical and endovascular repair of his peripherally seeded mycotic aneurysms.  相似文献   
5.
We reviewed 488 twin pregnancies that resulted in the birth of neonates weighing 1000 g or more. Complications were present in 56.7% of all pregnancies; most common were threat of premature labor (17.4%) and preeclampsia (14.5%). Perinatal mortality was 31.8 per thousand. Eighty percent of neonatal deaths in twin pregnancies involved newborns weighing less than 2000 g. Twin pregnancies are high risk pregnancies and benefit from early diagnosis, prevention and treatment of the threat of premature birth.  相似文献   
6.
7.
Groups of children (mean age, 31.4 months) with Haemophilus influenzae type b meningitis, epiglottitis, or septic arthritis were tested for the presence and levels of bacteremia, capsular polyribophosphate (PRP) antigenemia, and development of specific antibody in serum after the onset of acute illness. Although bacteremia cleared promptly after antibiotic therapy, circulating PRP could be detected in serum for relatively long periods, with 51% of the patients still having detectable antigen after 30 days postinfection. Even in the presence of specific antibody, antigenemia persisted for as long as 47 days after admission. It was observed that there was no statistically significant correlation between the persistence of antigenemia and age (P greater than 0.2), the initial antigen concentration (P greater than 0.50), or the development of antibody (P greater than 0.20). The presence of a low magnitude of bacteremia (less than 300 organisms per ml) was associated with a maximum concentration of 10 ng of PRP per ml. On the other hand, bacterial counts in excess of 10(4)/ml were associated with greater than 1,000 ng of PRP per ml (r = 0.98, r2 = 0.96, P less than 0.001). It was observed that the amount of circulating PRP in the acute phase of illness was related to whether a child developed convalescent-phase antibody. Invariably, the younger children, who primarily had meningitis, had a PRP concentration of greater than 10 ng/ml and failed to develop an antibody response in any isotype, whereas the older patients, who primarily had infections other than meningitis, had a PRP concentration of less than 10 ng/ml and a 45.5% success rate in developing an antibody response (P = 0.006). These findings suggest that there is a direct correlation between the magnitudes of bacteremia and antigenemia, that antigen may persist for long periods even in the presence of antibody, and that the level of antigenemia in addition to the patient age is significantly related to the nature of the convalescent-phase antibody response.  相似文献   
8.
Seven trypanosome stocks isolated have been characterized by lectin agglutination, isoenzyme analysis, and the end products excreted. The stocks were isolated from different geographic areas—one from Mexico (TM5), and six from Peru, four of these isolated from different species of triatoma (TP504, TP702, TP704 and TP706), the other two isolated from the salivary glands of Rhodnius ecuadorensis (TRa605 and TRa606). Additionally, one strain of Trypanosoma cruzi isolated from a human case (strain TC-Maracay) and one strain of T. rangeli (TRa, Cajamarca-Peru strain), characterized and maintained in our laboratory, were used as reference strains. According to statistical study, the stocks were grouped into three clusters: (1) cluster I included the reference strain of T. cruzi (TC-Maracay); (2) cluster II was subdivided into two groups—subcluster IIA for the Mexican isolate (TM5) and subcluster IIB for the Peruvian ones, isolated from the salivary glands of Rhodnius ecuadorensis (TRa 605 and TRa 606) and the reference strain T. rangeli (TRa); these two new isolates were classified as T. rangeli; and (3) cluster III for the rest of the Peruvian isolates, which should be considered at least as a different strain from the T. cruzi strain Maracay. We show that the identification of T. cruzi and T. rangeli in mixed infections is readily achieved by biochemical methods. These findings identified three clusters of Mexican and Peruvian stocks that correlate with geographic origin, although assignment to a T. cruzi linage was not possible.  相似文献   
9.
Introduction

Latina and African American women have elevated risk for perinatal depression and anxiety but have low rates of treatment engagement. Amid significant improvements in narrowing the digital divide, the number of technology-based mental health interventions has increased. A technology-based mode of delivery is important to consider because it can increase patient engagement and should inform program development. This review aimed to assess the mode of technology used for preventing and/or treating perinatal depression and anxiety in Latina and African American women, examine symptom management, and describe participant satisfaction.

Methods

We used PubMed, CINAHL, PsycINFO, PsycARTICLES, EBSCO, and Social Services Abstracts to identify studies that used technology (e.g., smartphones) to prevent and/or treat depression and/or anxiety in Latina and/or African American perinatal women. To be eligible for inclusion, studies must have had at least 50% Latina and/or African American samples. The review was conducted between November 2018 and October 2019, with no set publication start date.

Results

Of 152 studies reviewed, six met the inclusion criteria. Four studies included African American women; two studies had samples that were mostly composed of Latina women. Three studies used telephone/smartphone (e.g., text messaging) and three implemented internet-based interventions. All studies addressed depression; one focused on anxiety. The findings demonstrated participant satisfaction and promise for symptom management.

Discussion

Despite the limited number of studies that used technology to engage Latina and African American perinatal women, the results suggest that these women were willing to participate in digital interventions to address perinatal depression and anxiety.

  相似文献   
10.
While vascular endothelial cells are repeatedly stretched by the pulsatile nature of cardiac output, in vitro models traditionally used to study vascular biology involve static culture techniques. We have recently shown that pulsatile stretching of endothelial cells in culture will increase their rates of proliferation and regulate their secretion of macromolecules. The aim of this study was to determine whether membrane adenylate cyclase is involved in intracellular signalling during pulsatile stress. Bovine aortic endothelial cells were seeded on flexible-bottomed culture wells (3 x 10(5) cells/25 mm well) and allowed to attach for 48 hours. The culture wells were placed in a vacuum-operated stress providing instrument and subjected to 0.5 s of 24% strain, 0.5 s relaxation (60 cycles/min) for 0, 1, 3, 5, 7, 10 and 15 minutes (N = 24 wells/time point). Cells were homogenized and a crude membrane preparation (27,000 x g) was assayed for adenylate cyclase under basal and forskolin (100 microM) stimulated conditions. The results indicate that there is a time-dependent increase in both basal and stimulated adenylate cyclase with cyclic deformation and suggest that there may be a "stretch receptor" coupled to adenylate cyclase which can modulate endothelial cell function with hemodynamic changes.  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