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   439篇
  免费   29篇
  国内免费   6篇
儿科学   28篇
妇产科学   3篇
基础医学   53篇
口腔科学   8篇
临床医学   34篇
内科学   99篇
皮肤病学   5篇
神经病学   11篇
特种医学   91篇
外科学   38篇
综合类   7篇
一般理论   1篇
预防医学   26篇
眼科学   6篇
药学   42篇
肿瘤学   22篇
  2022年   4篇
  2021年   6篇
  2020年   1篇
  2019年   4篇
  2018年   9篇
  2017年   4篇
  2016年   8篇
  2015年   7篇
  2014年   6篇
  2013年   17篇
  2012年   9篇
  2011年   8篇
  2010年   17篇
  2009年   18篇
  2008年   12篇
  2007年   11篇
  2006年   16篇
  2005年   12篇
  2004年   3篇
  2003年   6篇
  2002年   8篇
  2001年   3篇
  2000年   2篇
  1999年   9篇
  1998年   25篇
  1997年   28篇
  1996年   30篇
  1995年   22篇
  1994年   25篇
  1993年   18篇
  1992年   9篇
  1991年   5篇
  1990年   9篇
  1989年   14篇
  1988年   6篇
  1987年   9篇
  1986年   11篇
  1985年   7篇
  1984年   5篇
  1983年   6篇
  1982年   4篇
  1981年   9篇
  1980年   7篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   10篇
  1975年   3篇
  1969年   1篇
  1966年   1篇
排序方式: 共有474条查询结果,搜索用时 15 毫秒
91.
The entorhinal cortex (ERC) has been implicated in schizophrenia by a number of studies. There is anatomical observation of neuronal heterotopias in the rostral ERC, which is consistent with a hypothesis of neurodevelopmental abnormalities in this disease. In view of the significant cytoarchitectonic variation of the ERC throughout its rostro-caudal extent, we performed a detailed subareal analysis of the rostral two-thirds of the entorhinal cortex (ERCr) in 14 postmortem schizophrenic brains and 14 matched controls (mean ages of 48 and 47 respectively). This systematic evaluation included both a qualitative microscopic analysis of morphogenetic anomalies that would be consistent with neurodevelopmental pathology and quantitative measurements of total neuronal number, average neuronal density, laminar volume and laminar depth from the cortical surface in cytoarchitectonically matched subareas of schizophrenic and control brains. Parcellation of the entire ERC on the basis of cytoarchitectonic criteria identified five distinct regions, similar to those described in the macaque, except that in the human brain three of the regions were further divisible into two or three subareas, yielding nine distinct cellular compartments. Five rostral areas, prorhinal (Pr), lateral (28L), intermediate rostral and caudal (281r and 281c), and sulcal (28S), comprise the ERCr. Gross and microscopic examination of these subdivisions throughout the ERCr failed to reveal laminar disorganization in any of the schizophrenic brains. The brains also did not differ significantly with respect to total neuronal number, total volume and neuronal density per laminar and subareal subdivision, or laminar thickness per entorhinal subarea. However, neuronal number and density were reduced by 12-18% in Pr and 28L, suggesting that mild quantitative abnormalities may exist in the ERCr and might possibly be revealed in a larger sample of schizophrenic brains. We have failed to confirm previous reports of laminar disorganization in the ERCr in brains of patients with schizophrenia; to the extent that this region is implicated in schizophrenia, the structural changes are likely to consist of more subtle cellular disturbances.   相似文献   
92.
The beta2 integrin (CD 18/CD 11 a, b, c) family of proteins mediate adherence of leukocytes to vascular endothelium and the associated ligand, intercellular adhesion molecule-1 (ICAM-1; CD 54), interacts with beta2 integrin proteins to allow transendothelial migration of leukocytes into sites of inflammation. The present study examines the function of these proteins in a murine model of acute cutaneous inflammation induced following topical application of 12-O- tetradecanoylphorbol-13-acetate (TPA) to the dorsal epidermis of SENCAR mice and in a model of skin multistage carcinogenesis. At 24 h following topical application of TPA to the dorsal epidermis of mice, dermal leukocytes expressed higher levels of beta2 integrin protein compared with the lower levels of beta2 integrin protein expression by peripheral blood leukocytes. ICAM-1 protein was localized to epidermal keratinocytes and vascular endothelium in TPA-treated skin and to proliferating papilloma cells. Intravenous (i.v.) injection of either 50 microg anti-beta2 integrin antibody alone or in combination with anti-ICAM-1 antibody significantly inhibited both TPA-stimulated neutrophil infiltration into the dermis (P < 0.001) and myeloperoxidase (MPO) activity (P < 0.03 anti-beta2 integrin antibody; P < 0.01 anti- beta2 integrin + ICAM-1 adhesion molecule antibodies), but had no effect on TPA-induced epidermal hyperplasia. In addition, injection of either anti-ICAM-1 adhesion molecule antibody alone (P < 0.004) or in combination with anti-beta2 integrin antibody (P < 0.001) significantly inhibited TPA-induced production of 7,8-dihydroxy-2'-deoxyguanosine (8- OHdG) immunoreactive proteins by epidermal keratinocytes. Beta2 integrin/ICAM-1 adhesion molecules work in concert to regulate migration, retention and functional activation of leukocytes within the dermis during TPA-induced skin inflammation and within stromal tissue of papillomas that form during multi-stage carcinogenesis. Agents that inhibit these receptor/ligand interactions may be useful in defining the roles of specific cell populations in cutaneous inflammation and multistage carcinogenesis and may also have potential as anti-promoting and anti-progression agents.   相似文献   
93.
McKeown-Eyssen (Cancer Epidemiol. Biomarkers Prevent., 3, 687-695, 1994) and Giovannucci (Cancer Causes Control, 6, 164-179, 1995), noting the striking similarity in lifestyle risk factors for colorectal cancer and insulin resistance, proposed that the hyperinsulinemia, glycemia and hypertriglyceridemia associated with insulin resistance promotes colon cancer. To compare the effect of diet on colon cancer promotion and insulin resistance in the F344 rat, we assessed the effect of fat, n-3 fatty acids and energy in pairwise comparisons on average size of aberrant crypt foci (ACF) and on glucose intolerance in the same animals in a single experiment. Diets high in fat and energy increased and diets with increased n-3 fatty acids and calorie restriction decreased both ACF growth and glucose intolerance compared with control diets. The measures of promotion of colon cancer and insulin resistance were strongly correlated (n = 98, r = 0.67, P < 0.001). In addition, both were highly correlated with daily energy intake (r = 0.62 and 0.66) and were also correlated with basal (post-prandial) insulin, glucose and triglycerides (r = 0.31-0.53, P < 0.01). We concluded that ACF growth and glucose intolerance are correlated for a wide range of diets and that increased circulating energy (glucose and triglycerides) may lead to both colon cancer promotion and insulin resistance.   相似文献   
94.
一阶导数差示脉冲极谱法的建立及在药物分析中的应用   总被引:11,自引:0,他引:11  
梁云爱  张天民 《药学学报》1992,27(2):135-138
本文研究了一阶导数差示脉冲极谱法,并将其运用于扑尔敏、氟哌啶醇、维生素B6及其制剂的定量分析中。方法简便、快速、灵敏、结果准确。  相似文献   
95.
Swerlick  RA; Eckman  JR; Kumar  A; Jeitler  M; Wick  TM 《Blood》1993,82(6):1891-1899
Important complications in sickle cell anemia occur secondary to vascular occlusion, which is postulated to be initiated by interactions of erythrocytes with vascular endothelial cells. In patients with sickle cell anemia, up to 25% of reticulocytes express the alpha 4 beta 1-integrin complex. Furthermore, erythrocytes from patients with sickle cell anemia bind to endothelial cells activated by tumor necrosis factor alpha via (TNF alpha) via interactions between erythrocyte alpha 4 beta 1 and endothelial cell vascular cell adhesion molecule-1 (VCAM- 1). Thus, binding of alpha 4 beta 1-expressing reticulocytes to cytokine-activated endothelial cells may initiate vascular complications in sickle cell anemia and perhaps other hemolytic anemias during episodes of infection and inflammation.  相似文献   
96.
Immunity in cattle vaccinated against ringworm   总被引:1,自引:0,他引:1  
A. Rybniká&#;  J. Chumela  V. Vrzal  V. Krupka 《Mycoses》1991,34(9-10):433-436
Protective properties of a live, freeze-dried vaccine against ringworm, produced by Bioveta, Ivanovice na Hané, Czechoslovakia, were tested in a group of 422 calves. Vaccinated and control calves were challenged by epicutaneous inoculation of a virulent culture of Trichophyton verrucosum. Between 4.4 and 9.5% of calves challenged between days 14 and 25 after revaccination showed only mild clinical signs of ringworm and 99-100% were fully protected from day 28, the immunity persisting for at least one year. All control calves showed signs of ringworm after challenge. In most cases, extensive mycotic lesions, also penetrating into deep skin layers, were observed. Protective properties of the Czechoslovak vaccine and a USSR vaccine were high and comparable.  相似文献   
97.
98.
The entorhinal cortex (ERC) has been implicated in the pathophysiology of Alzheimer's disease, schizophrenia and other disorders affecting cognitive functions. While powerful anatomical and histochemical methods (immunohistochemistry, in situ hybridization, etc.) may be applied (although with limitations) to postmortem human brain, each analysis should utilize a cytoarchitectonic approach to provide appropriate comparisons within the subdivisions of the ERC. Accordingly, we describe here the normal cyto- and myeloarchitecture of the human ERC as a prerequisite for the accompanying study of this region in schizophrenia. Our parcellation of this cortex differs from previous treatments in three ways. First, we adopted specific criteria of inclusion to define each subdivision of the region. Although distinctive ERC features are most prominent in the intermediate portion of this region, at least one of these features was considered the minimum necessary criterion to include adjacent tissue in the entorhinal area. Second, we used morphometric measurements (neuronal size and density as well as subdivisional volume and laminar thickness) to support our qualitative evaluation. Third, we have applied to the human ERC the conventional cytoarchitectonic nomenclature of the entorhinal cortex used previously in studies of non-human primates. This allows a more accurate extrapolation of the available numerous experimental anatomical, physiological and psychological data on this region to the human. As in the monkey, the five main subareas were recognized in the human (prorhinal, lateral, intermediate, sulcal and medial) but three required further subdivision (intermediate, sulcal and medial). The morphometric results obtained suggested a progression of the human entorhinal cortex from the peripheral to the central subareas, with the intermediate subarea (281) as the most complete entorhinal subdivision. Compared with non-human primates, the human ERC not only retains the basic periallocortical organization but also demonstrates further evolution. Taken together with available experimental data on the connectivity of this brain region, these results provide an anatomical basis for evaluating the ERC in human behavior.   相似文献   
99.
100.
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