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   30908篇
  免费   1901篇
  国内免费   158篇
耳鼻咽喉   266篇
儿科学   437篇
妇产科学   318篇
基础医学   4628篇
口腔科学   929篇
临床医学   2982篇
内科学   7403篇
皮肤病学   454篇
神经病学   3484篇
特种医学   1858篇
外科学   4163篇
综合类   177篇
一般理论   11篇
预防医学   1272篇
眼科学   600篇
药学   1718篇
中国医学   53篇
肿瘤学   2214篇
  2024年   28篇
  2023年   264篇
  2022年   440篇
  2021年   818篇
  2020年   505篇
  2019年   705篇
  2018年   788篇
  2017年   613篇
  2016年   875篇
  2015年   991篇
  2014年   1244篇
  2013年   1525篇
  2012年   2493篇
  2011年   2512篇
  2010年   1505篇
  2009年   1349篇
  2008年   2207篇
  2007年   2220篇
  2006年   2142篇
  2005年   2013篇
  2004年   1745篇
  2003年   1651篇
  2002年   1544篇
  2001年   266篇
  2000年   193篇
  1999年   277篇
  1998年   304篇
  1997年   225篇
  1996年   163篇
  1995年   151篇
  1994年   123篇
  1993年   88篇
  1992年   62篇
  1991年   65篇
  1990年   41篇
  1989年   59篇
  1988年   36篇
  1987年   34篇
  1986年   35篇
  1985年   30篇
  1984年   30篇
  1983年   34篇
  1982年   34篇
  1981年   29篇
  1980年   27篇
  1938年   24篇
  1937年   30篇
  1936年   25篇
  1935年   35篇
  1934年   22篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
91.
92.
Conclusion The past decade has seen extraordinary progress in the study of autosomal-dominant polycystic kidney disease. The 2 major genes for this disorder have been identified. Animal models of ADPKD have been produced. The molecular basis of the disease has been characterized. ADPKD is a “second-hit” disease, much like many cancer predisposition syndromes. This has profound implications for our understanding. The progression of ADPKD in individual patients is likely related more to their individual rate of acquisition of second hits at thePKD1 orPKD2 locus than to the inherited germ line mutation itself. Therapeutic approaches will perhaps now be considered, which will include interventions that may limit the rate at which somatic mutations occur in the kidney. The major focus of research at present is to elucidate the normal functions ofPKD1 andPKD2. Protein binding partners are being sought for both proteins. The possible calcium channel function ofPKD2 is being investigated. The downstream effects of cellular deficiency of either protein are likely to yield many clues. Modifying genetic factors that may independently affect disease progression are likely to be identified using the several mouse models. Perhaps the next decade will bring great strides in understanding and in potential therapy for this common disease. This paper was presented at the 2nd International Forum “The Frontiers of Nephrology,” Tokyo, May 10, 1998.  相似文献   
93.
The present study addressed auditory processing in 8-11-year-old children with developmental dyslexia by means of event-related brain potentials (ERP). Cortical sound reception was evaluated by recording N250 responses to syllables and tones and cortical sound discrimination by analyzing the mismatch negativity (MMN) to syllable and tone changes. We found that both cortical sound reception and sound discrimination were impaired in dyslexic children. The analysis of the data obtained from two dyslexic subgroups, Dyslexics-1 being impaired in non-word reading (or both non-word and frequent word reading) and Dyslexics-2 in frequent word reading but not in non-word reading, revealed that the MMN was specifically diminished in the latter group whereas it was normal-like in Dyslexics-1. However, no differences were found between these subgroups in sound reception as indicated by the responses elicited by the standard stimuli. These results show that different diagnostic subgroups of dyslexics have different patterns of auditory processing deficits as suggested by similarly impaired sound reception in both dyslexic groups and the sound-discrimination impairment specific to one of the groups.  相似文献   
94.
95.
96.
T-helper (Th) cells play an important role in orchestrating the effector function of CTL in anti-tumor immunity. However, only a limited number of Th cell epitopes has been characterized. Here we describe a novel approach for identifying naturally processed and presented peptides derived from chosen antigens. This method combines a transfection step of antigen-presenting cells with a vector encoding a fusion protein between the Ii chain and the antigen of interest, elution of the HLA-bound peptides and identification of the antigen-derived peptides by mass spectrometric comparison to the non-transfected cells. In vitro-stimulated Th cells against the identified peptide of interest specifically recognize transfectants overexpressing the cognate antigen. Using this approach, we were able to identify the HLA-DR4-restricted Th cell epitope NPPSMVAAGSVVAAV derived from cyclin D1, which is frequently overexpressed in tumors. This method will help in identifying peptide candidates for vaccination studies for tumor immunotherapy.  相似文献   
97.
Murine macrophages were treated with various doses of cyclosporin A (CsA) to enhance the killing of Leishmania major parasites. CsA reduced the rate of infected cells from 75% in non-treated controls to less than 15% with 1 micro g CsA/ml in a dose-dependent manner. The leishmanicidal effect was also observed when CsA was added 48 h after the infection of macrophages. In contrast, FK506, another structural non-related immunosuppressive drug with antiparasitic activities, showed no effect on the ability of macrophages to kill intracellular Leishmania parasites. Since nitric oxide has been identified as a key molecule for the leishmanicidal function of macrophages, we analyzed the role of this molecule. There was no influence on the leishmanicidal effect of CsA when L- N-(1-iminoethyl)lysine, a potent and selective inhibitor of mouse inducible nitric oxide synthase, was added. Furthermore, the presence of the macrophage-inhibiting cytokines interleukin (IL)-10 and IL-13 simultaneously or prior to CsA did not inhibit leishmania killing, while both cytokines completely prevented parasite killing by macrophages activated with gamma interferon and tumor necrosis factor (TNF). CsA was fully active on macrophages from TNF-receptor p55 knockout mice arguing against autocrine activation by TNF. We therefore conclude that the antileishmanial effect of CsA is independent of effector mechanisms employed by macrophage-activating cytokines.  相似文献   
98.
Quartz glass electrodes are superior to conventional glass electrodes for low-noise recording. They have better electrical characteristics and hydrophobic surfaces which resist creeping of salt solutions. We used oxy-hydrogen heating with program-controlled gas pressure to melt quartz glass capillaries. Usually, the relative wall thickness (the quotient of the outer and inner diameters do/di) of capillaries is, at best, maintained up to the electrode tip. If tips with thicker walls can be produced, coating and other surface treatments can be avoided. We found that programmed heating periods without pull allowed an fivefold increase of do/di in the tip region. Since do/di is inversely proportional to input capacity, the recording noise was minimized and became insignificant relative to amplifier and holder noise. A sample patch-clamp recording is shown.  相似文献   
99.
The influence of the destruction of the catecholaminergic (CA) system on the reactions of neurons of the somatosensory zone of the cortex elicited by stimulation of the sciatic nerve, and on the features of the modulation of these reactions following the stimulation of the region of the basal nuclei (source of cholinergic innervation of the neocortex) and the microiontophoretic application of acetylcholine (ACh), was investigated in mongrel infant rats, 21–31 days of age. It was demonstrated that destruction of the CA system in newborn rats increases the reactivity of neurons somatosensory cortex to sensory stimulation, has no influence on the modulating effect of the cholinergic system, of the forebrain, and leads to intensification of the modulating influence of applied ACh [2].Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 42, No. 5, pp. 1018–1022, September–October, 1992.  相似文献   
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