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   357篇
  免费   11篇
儿科学   7篇
妇产科学   1篇
基础医学   77篇
口腔科学   3篇
临床医学   31篇
内科学   40篇
皮肤病学   3篇
神经病学   24篇
特种医学   25篇
外科学   38篇
综合类   36篇
预防医学   33篇
眼科学   9篇
药学   30篇
肿瘤学   11篇
  2021年   4篇
  2019年   4篇
  2018年   5篇
  2017年   4篇
  2016年   6篇
  2015年   4篇
  2014年   13篇
  2013年   11篇
  2012年   12篇
  2011年   11篇
  2010年   22篇
  2009年   18篇
  2008年   10篇
  2007年   11篇
  2006年   8篇
  2005年   7篇
  2004年   9篇
  2003年   6篇
  2002年   3篇
  2001年   9篇
  1999年   6篇
  1998年   15篇
  1997年   7篇
  1996年   6篇
  1995年   6篇
  1994年   11篇
  1993年   4篇
  1992年   4篇
  1991年   13篇
  1990年   15篇
  1989年   14篇
  1988年   6篇
  1987年   8篇
  1986年   7篇
  1985年   8篇
  1984年   2篇
  1980年   4篇
  1978年   4篇
  1976年   6篇
  1975年   2篇
  1972年   4篇
  1971年   2篇
  1970年   3篇
  1969年   3篇
  1968年   4篇
  1967年   6篇
  1966年   2篇
  1959年   2篇
  1939年   2篇
  1936年   2篇
排序方式: 共有368条查询结果,搜索用时 15 毫秒
31.
To investigate the effect of Herpes Simplex virus (HSV) on spermatogenesis, HSV in ejaculate was detected by a rapid cultural method in 268 infertile males and 47 healthy ones. The number of mobile spermatozoa in HSV infected samples was less than in non-infected samples (21 mln/mlversus 40 mln/ml, p = 0.0001). The relative number of morphologically normal gametes was 13% versus 19% (p = 0.002), respectively. The quantitative karyological test discovered that males with HSV-infected ejaculate have more degenerating sex cells while in high virus contamination (more than 10 virus particles in 1 ml) the number of spermatides and spermatocytes of the 1 order at diploten stage is low. Organic testicular culture was used for more detailed study of pathogenetic mechanisms of HSV impact on spermatogenesis. Testicular explants infection was associated with reduction in the number of spermatogones, spermatocytes and spermatides on culturing week 2. The above findings reveal some pathogenetic mechanisms underling fertility disorders in males with HSV infection: a gametotoxic effect of the virus reducing populations of spermatogones, spermatocytes and spermatide; affected mobility and morphological characteristics of spermatozoa. Detection of the mechanisms of HSV action on spermatogenesis opens a perspective of antivirus drug administration in combined treatment of male infertility.  相似文献   
32.
BACKGROUND: Brainstem gliomas are highly heterogeneous tumors both in their clinical manifestation and in their pathology. Despite significant advances in the surgery for brainstem gliomas many aspects of this pathology are still unelear. OBJECTIVE: To evaluate the clinical, radiological and surgical outcome of 40 focal "intrinsic" brainstem gliomas and propose a surgical strategyoriented classification. MATERIALS AND METHODS: A total of 40 focal ‘intrinsie’ ("expanding variety") tumors have been operated over a period of 8.5-years (January 1998-June 2007). Our criteria included patients with (1) well-defined gadolinium enhancing tumor, (2) relatively long duration of symptoms (〉 six months) and (3) good neurological functional status and independent for all activities of davy living. The cutoff size of 2 cm was not rigidly adhered to. RESULTS: The "intrinsic" brainstem tumors were classified into three types: Expanding, diffuse infiltrative and pure ventral varieties.  相似文献   
33.
34.
The work analyzes causes of high blood loss in operations under conditions of nonperfusion deep hypothermia. It was found to be related with the division of massive adhesions in the preocclusive period and with the presence of prolonged heparinemia after occlusion. A combination of a minimal trauma of adhesions, reliable surgical hemostasis, early suturing the wound of the chest and early neutralization of activity of heparin allowed the operation blood loss to be 2.4 times less and the postoperative blood loss--2.7 times less.  相似文献   
35.
36.
Experiments were performed on Norwegian rats selected over more than 59 generations for high and low levels of high-affective defensive aggressivity and on highly aggressive (offensive) Tg8 mice with irreversible monoamine oxidase A knockout. There were significant differences in the functional state and expression of 5-HT1A receptors between highly aggressive and non-aggressive animals. Functional activity assessed in terms of hypothermia evoked by a 5-HT1A agonist was significantly greater in non-aggressive rats and mice than in aggressive animals. The high level of functional activity in non-aggressive rats coincided with a greater level of expression of 5-HT1A receptors in the midbrain. The level of 5-HT1A receptor mRNA in aggressive mice was unchanged in the midbrain and hypothalamus and was increased in the frontal cortex and amygdaloid complex. These results led to the conclusion that 5-HT1A receptors play a significant role in the mechanisms of genetic predisposition to aggressive behavior. __________ Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 56, No. 4, pp. 537–542, July–August, 2006.  相似文献   
37.
38.
The analysis of blood loss in profound perfusion-free hypothermia has shown that its main cause is that heparin neutralization was performed only after the warming of a patient to 34-35 degrees C. The results of in vitro studies have shown that heparin was effectively neutralized by protamine sulfate at room temperature (20 degrees C). Using protamine sulfate, heparin neutralization was performed at 25-27 degrees C in 90 patients, which reduced blood loss by 10-15% of the circulating blood volume and made it possible to avoid hemotransfusions in the post-operative period.  相似文献   
39.
Central hemodynamic parameters were retrospectively studied in 284 patients. After aortic declamping, sinus rhythm spontaneously restored in 179 patients (Group 1), ventricular fibrillation occurred in 105 (Group 2). The preoperative parameters were similar in both groups. The number of grafts and the time of aortic clamping and cardiopulmonary bypass (CPB) were higher in Group 1. In the groups, the volume of cardioplegic solution and the average dose of phenylephrine and nitroglycerin per perfusion did not differ. After CPB, the values of cardiac output (CO) and cardiac index (CI) were significantly higher in Group 1 than in Group 2. At the end of an operation and 3 hours after its termination, there were no differences between two groups. Twelve hours after surgery, cardiac output and systolic blood pressure were significantly higher in Group 1. Following 24 hours of surgery, heart rate was significantly greater in Group 1 than in Group 2 After surgery, all hemodynamic parameters were within normal physiological values. The mean duration and the degree of inotropic support did not differ in the groups. The incidence of atrial fibrillation, perioperative myocardial infarction, and low cardiac output syndrome were comparable in both groups. Thus, various modes of cardiac performance recovery affect perioperative hemodynamics; however, this impact is insignificant and does not make management policy be changed in such patients. After aortic declamping, ventricular fibrillation requiring for defibrillation is not a clinical sensitive factor that negatively affects the intra- and postoperative period.  相似文献   
40.
Virus diversity and escape from immune responses are the biggest challenges to the development of an effective vaccine against HIV-1. We hypothesized that T-cell vaccines targeting the most conserved regions of the HIV-1 proteome, which are common to most variants and bear fitness costs when mutated, will generate effectors that efficiently recognize and kill virus-infected cells early enough after transmission to potentially impact on HIV-1 replication and will do so more efficiently than whole protein-based T-cell vaccines. Here, we describe the first-ever administration of conserved immunogen vaccines vectored using prime-boost regimens of DNA, simian adenovirus and modified vaccinia virus Ankara to uninfected UK volunteers. The vaccine induced high levels of effector T cells that recognized virus-infected autologous CD4+ cells and inhibited HIV-1 replication by up to 5.79 log10. The virus inhibition was mediated by both Gag- and Pol- specific effector CD8+ T cells targeting epitopes that are typically subdominant in natural infection. These results provide proof of concept for using a vaccine to target T cells at conserved epitopes, showing that these T cells can control HIV-1 replication in vitro.  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