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   492篇
  免费   28篇
  国内免费   9篇
儿科学   36篇
妇产科学   1篇
基础医学   54篇
口腔科学   7篇
临床医学   40篇
内科学   92篇
皮肤病学   18篇
神经病学   74篇
特种医学   60篇
外科学   38篇
综合类   6篇
预防医学   34篇
眼科学   23篇
药学   20篇
中国医学   2篇
肿瘤学   24篇
  2022年   4篇
  2021年   10篇
  2020年   7篇
  2019年   4篇
  2018年   7篇
  2017年   6篇
  2016年   10篇
  2015年   5篇
  2014年   15篇
  2013年   27篇
  2012年   11篇
  2011年   8篇
  2010年   28篇
  2009年   12篇
  2008年   7篇
  2007年   10篇
  2006年   18篇
  2005年   8篇
  2004年   10篇
  2003年   10篇
  2002年   7篇
  2001年   9篇
  2000年   11篇
  1999年   14篇
  1998年   25篇
  1997年   17篇
  1996年   17篇
  1995年   22篇
  1994年   11篇
  1993年   14篇
  1992年   7篇
  1991年   10篇
  1990年   6篇
  1989年   18篇
  1988年   12篇
  1987年   17篇
  1986年   19篇
  1985年   15篇
  1984年   9篇
  1983年   5篇
  1982年   5篇
  1981年   5篇
  1980年   6篇
  1979年   5篇
  1977年   3篇
  1974年   3篇
  1973年   4篇
  1972年   2篇
  1971年   2篇
  1966年   3篇
排序方式: 共有529条查询结果,搜索用时 15 毫秒
1.
2.
We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients.  相似文献   
3.
4.
5.
6.
Changes in astrocyte glutamine synthetase (GS) in postischemic rat brain were evaluated and correlated with regional neuronal vulnerability or resistance to ischemia. Rats subjected to 20 or 30 min of cerebral ischemia were allowed to survive for 3 or 24 h after ischemia; normal animals served as controls. Resultant neuronal necrosis was severe in the striatum by 24 h and in the CA1 region of the hippocampus at 72 h; neurons in paramedian cortex and CA3 region of the hippocampus were not permanently damaged. Glutamine synthetase (GS) immunocytochemistry was performed on vibratome sections of paraformaldehyde-fixed brains and enzyme activity was assayed in frozen samples of cerebral cortex, striatum and hippocampus. At 3 and 24 h after ischemia, GS immunoreactivity increased and was secondary to enlargement of GS-positive cell bodies and processes as well as to increased numbers of GS-positive astrocytes. Enzyme activity also increased in cortex, striatum and hippocampus at 3 and 24 h (P less than or equal to 0.03). This study shows that increase in astrocyte GS occurs rapidly after ischemia, and prior studies indicate that this increase occurs in parallel with proliferative changes in astrocyte organelles. The results also suggest that astrocyte metabolism of glutamate increases after ischemia. The increased capacity for glutamine synthetase may be important in normalizing extracellular glutamate following ischemia and protecting brain from the neurotoxic effects of this excitatory amino acid.  相似文献   
7.
8.
Visually guided, spatially oriented behavior involves an ongoing integration of signals regarding the loci of the retinal images and the position and orientation of the eye. In the strabismic this requires an altered spatial metric resulting from a functional readaptation to avoid confusion and diplopia. A comparator mechanism for evaluating these two signals is presented. A case report using "disruptive" therapeutic procedures that deliberately alter the strabismic's visual-postural control system is presented. A treatment plan for altering the anomalous binocular link, a characteristic of the well adapted strabismic, is described and related to the comparator mechanism.  相似文献   
9.
We have previously observed the repeated presence of low but detectable amounts of the trophoblast marker pregnancy-specific beta1-glycoprotein (SP1) in the serum of some women undergoing in-vitro fertilization (IVF) treatment around the time of oocyte retrieval. The occurrence of these signals seemed to be restricted to a defined group of patients which also showed a lower pregnancy success rate in a preliminary study. To test our hypothesis we have analysed 173 consecutive cycles leading to an embryo transfer. Fifty-four cycles (31%) had a serum SP1 level of at least 0.1 ng/ml between days embryo transfer -5 and embryo transfer (group A). Five pregnancies were obtained in this group (pregnancy rate = 9.3%), while in group B, defined by the absence of detectable SP1 before embryo transfer (119 cycles), 36 ongoing pregnancies were achieved (30.3%). Ten of the 41 pregnancies were achieved in 33 first-time non-pregnant patients undergoing further attempts during the study period. Again the pregnancy rate was higher in the first-time group B women (9/23 versus 1/10 for group A). Patients tended to remain in their groups A or B, the latter being associated with a better immediate as well as subsequent chance for pregnancy. Group A cycles had a significantly lower endometrial thickness two days before oocyte retrieval than group B (P = 0.0011). We postulate that the presence of an unknown, maternal and progesterone- or follicle stimulating hormone-independent factor in some patients could stimulate tonic ectopic SP1 synthesis and at the same time negatively influence endometrial development.   相似文献   
10.
The functional of B-L (Ia-equivalent)-positive (B-L+) adn -negative (B-L-) chicken peripheral blood lymphocytes (PBL) was studied in vitro and in vivo. The PBL were first stained in direct immunofluorescence tests with a fluorescein isothiocyanate-labelled anti-B-L alloantiserum and then separated by means of a fluorescence-activated cell sorter. In agreement with our previous findings, B-L- cells showed functional properties of T lymphocytes, responding to concanavalin A and phytohaemagglutinin-P in vitro and inducing a graft-versus-host (GVH) reaction when injected into allogeneic embryos. Sorted B-L+ gave no responses in any of these assays. Neither B-L+ nor B-L- cells, when tested alone, responded significantly to pokeweed mitogen, but mixtures of the two restored the responsiveness to that of the original unsorted suspension. Of the B-L+ PBL, 10% were T cells, which may account for the low GVH reactivity given by this population.  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