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   702篇
  免费   45篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   10篇
妇产科学   3篇
基础医学   157篇
口腔科学   3篇
临床医学   49篇
内科学   107篇
皮肤病学   33篇
神经病学   115篇
特种医学   24篇
外科学   128篇
综合类   1篇
预防医学   33篇
眼科学   13篇
药学   36篇
肿瘤学   35篇
  2022年   4篇
  2021年   6篇
  2020年   4篇
  2019年   7篇
  2018年   11篇
  2017年   3篇
  2016年   12篇
  2015年   20篇
  2014年   16篇
  2013年   23篇
  2012年   40篇
  2011年   41篇
  2010年   24篇
  2009年   33篇
  2008年   45篇
  2007年   47篇
  2006年   48篇
  2005年   52篇
  2004年   37篇
  2003年   37篇
  2002年   57篇
  2001年   10篇
  2000年   12篇
  1999年   11篇
  1998年   10篇
  1997年   9篇
  1996年   13篇
  1995年   7篇
  1994年   7篇
  1993年   6篇
  1992年   8篇
  1989年   3篇
  1988年   7篇
  1987年   3篇
  1985年   5篇
  1984年   5篇
  1983年   3篇
  1982年   4篇
  1981年   7篇
  1980年   5篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1975年   6篇
  1974年   3篇
  1973年   2篇
  1972年   4篇
  1969年   3篇
  1968年   2篇
  1967年   3篇
排序方式: 共有750条查询结果,搜索用时 531 毫秒
701.
Positron emission tomography (PET) with [18F]fluorodeoxyglucose [18F]FDG has evolved as a method of increasingly clinical importance in the management of patients with malignant lymphoma. However, inflammatory lesions also accumulate [18F]FDG and may cause difficulties with interpretation. This report deals with 2 patients with simultaneous occurrence of Hodgkin's lymphoma and eosinophilic granuloma, a rare but known coincidence of diseases. In the first case, Hodgkin's disease could not be differentiated from eosinophilic granuloma. Positron emission tomography showed increased [18F]FDG uptake both in lymphoma manifestations and in the granuloma. In the second case with proven Hodgkin's disease, post-treatment examination showed a positive PET lesion in the mediastinal residual mass, which was interpreted as viable lymphoma. However, histologic examination revealed that it was an eosinophilic granuloma.  相似文献   
702.
Among the so-called imported diseases the intestinal parasitoses occupy an important place. Examinations of 5,168 foreigners who entered our country in the district of Halle resulted in the most frequent invasiveness for Trichuris trichiura (whipworm) with 54.33%, Ascaris lumbricoides (eel-worm) with 26.90% and ancylostomatides (hookworms) with 17.88%. The Entamoeba histolytica could be proved in 1.90% of the test persons, the Giardia lamblia in 3.35%. The severest parasitism showed persons from East Asia as well as from tropical and subtropical regions of Africa and America; multiple infestations were not infrequent. With regard to the possibility of the importation of parasitic infectious diseases given by the increasing intercontinental contacts, for which there is generally receptivity in our area, recent increases of extensity in autochthonic parasitoses which could be extensively restrained by effective anti-epidemic measures cannot be excluded. This needs on principle consideration in the establishment of programmes of antiparasitic action.  相似文献   
703.
Three different rat strains, Sprague-Dawley, Wistar and Fischer 344, were treated for 3 months with 2 doses (0.8; 4 mg/kg) of the gastric acid suppressing ATPase inhibitor pantoprazole. The gastrin levels were determined, the height of the mucosa measured and the number of enterochromaffin-like (ECL) cells counted. Because these cells were stained according to the method of Grimelius they were designated as GPC (Grimelius positive cells). Under 4 mg/kg, the gastrin levels were increased 8 hours after administration, but fell again after 24 h. The Fischer rats showed the highest value. Also the height of the mucosa was increased under 4 mg/kg. A trend towards an increased mucosal height was noticeable even at 0.8 mg/kg. The number of GPC was determined in 2 ways: 1) without taking the mucosal height into account, 2) taking the height into account. An increase in GPC was observed at 4 mg/kg with both methods.  相似文献   
704.
The purpose of the present study was the evaluation of ultrastructural characteristics of the enterochromaffin-like (ECL) cells in the fundic mucosa of three different rat strains without treatment and after treatment with the H+, K(+)-ATPase inhibitor pantoprazole. In the study, 20 one year old female Sprague Dawley (SD), Fischer 344 (F) and Wistar (W) rats each were treated orally for three months with 4 mg pantoprazole/kg/d or with the vehicle only. The control animals showed close conformity of ECL cell density and morphology in all three strains. Treatment with pantoprazole led to a significant increase in serum gastrin concentration and GPC density in all strains. However, the electron microscopically determined ECL cell density was markedly increased in the SD strain only. Ultrastructurally all treated rats showed activation of the ECL cells, and enhanced histamine release. The SD and F strains had an enhanced proportion of large ECL cell granules, with the F rats also showing an increased granule density. In contrast, the treated W rats were found to have a lower granule density and a higher proportion of small and medium sized granules compared to their controls.  相似文献   
705.
In a previous report two additive scales were developed for measuring susceptibility to stimulation (with 4 experimental stimuli) and reactivity (with 4 types of reactions). The degree of loss of attention in neurological patients as determined by the position of a patient correlates with the frequencies of his reactions. Thus the measurement of frequencies does not add any further information. There is no patterning of reactions due to the different etiology of the disorder of attention. These results support the suggested one-factor theory of attention.  相似文献   
706.
Human fetal parietal cortical tissue was transplanted to cortical cavities in immunosuppressed rats. Protoplasmic astrocytes in the human cortical grafts highly expressed human angiotensinogen mRNA as identified with 35S-labeled and digoxigenin-labeled riboprobes combined with immunohistochemistry for glial fibrillary acidic protein. Antibodies to human specific neurofilament protein 70 KD were used to characterize neurons in the graft and fiber outgrowth into the host brain. Immunohistochemistry revealed human angiotensinogen-like immunoreactivity in many small protoplasmic astrocytes and very few large neurons. These results demonstrate that human angiotensinogen mRNA and protein is synthesized in immature human glia. We assume that angiotensinogen is transformed into angiotensin peptides, which may participate in the regulation of growth processes. The results suggest that human angiotensinogen may play a role during human ombryogenesis. © 1994 Wiley-Liss, Inc.  相似文献   
707.
In chloralose-anaesthetized cats the effects of intravenous application of the alpha 1- and alpha 2-adrenoceptor agonistic and antagonistic agents methoxamine, prazosin, B-HT 933 and rauwolscine were tested on baroreceptor reflex, sympathetic background activity and blood pressure. Sympathetic activity was recorded from the renal nerve and the efficacy of the central transmission of the baroreceptor reflex was measured by the duration of the complete inhibition of renal nerve activity during electrical stimulation of the left carotid sinus nerve. All baroreceptors were denervated by sectioning both carotid sinus and vagal nerves. The alpha 1-agonist methoxamine increased baroreceptor-induced sympatho-inhibition, sympathetic background activity and blood pressure. The alpha 1-antagonist prazosin had the opposite effects. The alpha 2-agonist B-HT 933 was most effective in augmenting the inhibitory response in sympathetic activity to baroreceptor stimulation; sympathetic background activity and blood pressure were also decreased. At low doses (50 micrograms/kg) the alpha 2-antagonist rauwolscine reduced the baroreceptor sympathetic reflex inhibition and increased sympathetic activity and blood pressure. The effect of B-HT 933 upon the baroreceptor reflex could be completely antagonized by rauwolscine. These findings demonstrate a very effective facilitation of the baroreceptor reflex transmission by stimulation of central alpha 2-adrenoceptors. Through such humoral-neuronal interaction circulating catecholamines are likely to modulate cardiovascular control.  相似文献   
708.
709.
Summary Due to the large number of differential diagnostic possibilities, the etiology of endogenous uveitis is still hard to determine. One reason for uveitis may be the occurrence of parasites. However, too little attention is paid to this underlying disease. Methods: To identify certain sources of infection, ovoscopic probes of 98 dog feces from the urban area of Halle were taken. The material was collected from children's playgrounds, parks and swimming pools. A retrospective analysis of patient case data from the records of the University Eye Hospital for the years 1986–1995 complemented the environmental and parasitological examination of patients with Toxocara canis and T. cati infections. Results: From the ovoscopic examinations, 16 % of the fecal samples contained T. canis eggs. Seventeen percent contained coccicidal sporocysts. Eggs of Trichuris vulpis and not clearly identifiable nematodal larvae were found in 1 % of the samples. The reasons for the morphology was, in one instance, suspected Echinococcus eggs. The fact that 12 or 15 parasitologically positive dog excrement samples were taken from the immediate vicinity of children's playgrounds and another three directly from these grounds should be regarded as particularly critical. The investigated patient case data records revealed for the period studied nine uveitic patients with T. canis infection. The diagnosis was based on the larva precipitation test in all cases. After correct diagnosis and appropriate treatment, the prognosis was favorable. The specific treatment had to be repeated in two patients. Conclusions: The environmental parasitological study presented proves the relatively high prevalence of pathogenic causal agents in dog excrement samples from the area of urban recreation and leisure grounds, in particular, children's playgrounds. Parasite infestation is a mirror of the efficiency of hygienic and social measures. Public health education must be reinforced. Differential diagnosis of chronic endogenous eye diseases must pay more attention to infections by parasites.   相似文献   
710.
Plectin, a major linker and scaffolding protein of the cytoskeleton, has been shown to be essential for the mechanical integrity of skin, skeletal muscle, and heart. Studying fibroblast and astroglial cell cultures derived from plectin (−/−) mice, we found that their actin cytoskeleton, including focal adhesion contacts, was developed more extensively than in wild-type cells. Also it failed to show characteristic short-term rearrangments in response to extracellular stimuli activating the Rho/Rac/Cdc42 signaling cascades. As a consequence, cell motility, adherence, and shear stress resistance were altered, and morphogenic processes were delayed. Furthermore, we show that plectin interacts with G-actin in vitro in a phosphatidylinositol-4,5-biphosphate-dependent manner and associates with actin stress fibers in living cells. The actin stress fiber phenotype of plectin-deficient fibroblasts could be reversed to a large degree by transient transfection of full-length plectin or plectin fragments containing the amino-terminal actin-binding domain (ABD). These results reveal a novel role of plectin as regulator of cellular processes involving actin filament dynamics that goes beyond its proposed role in scaffolding and mechanical stabilization of cells.  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