全文获取类型
收费全文 | 3638243篇 |
免费 | 257772篇 |
国内免费 | 9764篇 |
专业分类
耳鼻咽喉 | 49114篇 |
儿科学 | 120470篇 |
妇产科学 | 99946篇 |
基础医学 | 510924篇 |
口腔科学 | 102476篇 |
临床医学 | 333551篇 |
内科学 | 709576篇 |
皮肤病学 | 85955篇 |
神经病学 | 294128篇 |
特种医学 | 137871篇 |
外国民族医学 | 941篇 |
外科学 | 542980篇 |
综合类 | 78534篇 |
现状与发展 | 8篇 |
一般理论 | 1414篇 |
预防医学 | 278192篇 |
眼科学 | 84817篇 |
药学 | 265770篇 |
12篇 | |
中国医学 | 8238篇 |
肿瘤学 | 200862篇 |
出版年
2021年 | 28557篇 |
2019年 | 29214篇 |
2018年 | 41556篇 |
2017年 | 31661篇 |
2016年 | 36048篇 |
2015年 | 40893篇 |
2014年 | 56515篇 |
2013年 | 84148篇 |
2012年 | 113502篇 |
2011年 | 120063篇 |
2010年 | 71906篇 |
2009年 | 68202篇 |
2008年 | 111494篇 |
2007年 | 118643篇 |
2006年 | 120254篇 |
2005年 | 115342篇 |
2004年 | 110837篇 |
2003年 | 106580篇 |
2002年 | 102912篇 |
2001年 | 176125篇 |
2000年 | 180247篇 |
1999年 | 151589篇 |
1998年 | 43182篇 |
1997年 | 38016篇 |
1996年 | 38106篇 |
1995年 | 36924篇 |
1994年 | 33773篇 |
1993年 | 31649篇 |
1992年 | 117250篇 |
1991年 | 113101篇 |
1990年 | 109450篇 |
1989年 | 105752篇 |
1988年 | 96689篇 |
1987年 | 94712篇 |
1986年 | 88924篇 |
1985年 | 84895篇 |
1984年 | 63281篇 |
1983年 | 53701篇 |
1982年 | 31512篇 |
1979年 | 55981篇 |
1978年 | 39291篇 |
1977年 | 33442篇 |
1976年 | 31187篇 |
1975年 | 32987篇 |
1974年 | 39340篇 |
1973年 | 37598篇 |
1972年 | 35136篇 |
1971年 | 32596篇 |
1970年 | 30115篇 |
1969年 | 28795篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
Nonorganic failure-to-thrive is a medical-psychological disorder reflecting lack of growth in an infant without apparent physical causes. Children who fail to thrive as infants are at high risk for developmental delays, personality problems, abuse, and death. This article focuses on environmental failure-to-thrive, describing the behavioral characteristics of the nonthriving infant and the family milieu. Aspects of early environments of NOFT infants are profiled, specific intervention strategies are discussed, and recommendations regarding the promotion of intense, consistent multi-disciplinary intervention strategies are advanced. 相似文献
953.
954.
S A Meyer 《American family physician》1986,34(1):159-163
Although jejunoileal bypass surgery proved effective in controlling morbid obesity, the serious adverse effects from the operation were ultimately found to outweigh the benefits. Gastric partitioning results in weight loss by restricting the volume of food ingested rather than by interfering with absorption. Vertical banded gastroplasty has fewer complications than Roux-en-Y gastric bypass and is currently the surgical procedure of choice for morbid obesity. 相似文献
955.
956.
F S Che 《中华神经精神科杂志》1991,24(6):365-6, 385
The nuclear content, area and perimeter of the nucleus of lymphocytes in the C.S.F. were determined quantitatively by means of image analysis technique. 26 cases of central nervous system lymphocytic leukemia (CNLL), and 8 suspected cases were studied, other 56 cases who did not have leukemic and neoplastic diseases and had normal C.S.F. lymphocytes were taken as a control. Our data showed that all the mean nuclear content (MNC), mean nuclear area (MNA), mean nuclear perimeter (MNP), and the maximum and minimum nuclear contents of the 2 groups of former patients were obviously higher than those of the contral (P less than 0.01). These results presented suggestion that the image analysis technique can be used for differentiating the leukemic lymphocyte from normal one especially in suspected cases, and thus the diagnosis of CNLL might be improved. 相似文献
957.
Immunocytochemical methods have been used to examine the localisation of 3 neurofilament proteins and the calcium binding protein, calbindin D28k, in whole mount preparations of the submucous plexus in the Wistar rat. Neurofilament-M (160 kDA protein) was present in 40% of the submucosal neurons, staining fine filaments in the soma and the axonal processes. Calbindin D28k was present in 40% of the submucosal neurons staining both the soma and nerves within the plexus. The neurofilament proteins and calbindin D28k were never observed within the same neurons. Neurofilament-M was co-localised with substance P and calcitonin gene-related peptide but not somatostatin or the other neuropeptides investigated. Calbindib D28k was co-localised with vasoactive intestinal polypeptide and neuropeptide Y. Galanin- and somatostatin-immunoreactive neurons did not contain either the neurofilament proteins or calbindin D28k. The results demonstrate the presence of subsets of submucosal neurons that can be distinguished by the presence of neurofilament-M or calbinsin D28k. 相似文献
958.
We studied functional and immunohistochemical characteristics of cultured rat microglia. Unstimulated microglia did not proliferate. Microglia stimulated with LCM (L929 conditioned medium: colony stimulating factor-1) had proliferative activity and increased acid phosphatase activity. LPS (lipopolysaccharide) and IFN gamma (interferon-gamma) but did not affect proliferative activity. Immunohistochemically, RCA-1 lectin and GS-1 lectin, which react to beta-D-galactose and alpha-D-galactose respectively, strongly reacted to the cytoplasm and membrane of unstimulated microglia. After stimulation with LCM, microglia elongated processes and decreased response to these lectins. On the other hand, microglia stimulated with LCM showed increased reactivity to monoclonal antibody of vimentin. Microglia stimulated with LPS had round shape and had response to these lectins and vimentin. Microglia stimulated with IFN gamma had adhesive activity and weakly stained with these lectins but not with vimentin. ED-1 (monoclonal antibody of rat monocytes/macrophages) reacted to unstimulated and stimulated microglia. In flow cytometry, unstimulated microglia expressed OX-18 (MHC class I) and W3/25 (CD4) antigen. After stimulation with IFN gamma, microglia were induced to express these antigens. CD4 antigen is a marker of helper/inducer T cells and thought to be a receptor of HIV. The results that microglia had CD4 antigen which was further induced with IFN gamma are important to investigate infection of the CNS with HIV. OX-6 (Ia) antigen was induced with IFN gamma. This indicates that the microglia plays a central role in the CNS immune reaction. These characteristics of cultured rat microglia provide useful informations to investigate the pathogenesis of the CNS disorders. 相似文献
959.
K J Meador J L Thompson D W Loring A M Murro D W King B B Gallagher G P Lee J R Smith H F Flanigin 《Neurology》1991,41(6):869-872
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms. 相似文献
960.
J Elidan E Leibner S Freeman M Sela M Nitzan H Sohmer 《Electroencephalography and clinical neurophysiology》1991,80(2):140-145
We have succeeded in recording short and middle latency vestibular evoked responses in human subjects. The head was held rigidly in a special, patented head holder, constructed individually for each subject, which gripped the teeth of the upper jaw. The stimulus consisted of 2/sec steps of angular acceleration impulses produced by a special motor with intensities of about 10,000 degrees/sec 2 and with a rise time of 1-2 msec. The electrical activity was recorded as the potential difference between special forehead and mastoid electrodes having a large, secure contact area with the skin. The activity was digitally filtered and averaged in 2 separate channels by means of a Microshev 2000 evoked response system. The short latency responses, with peaks at about 3.5 msec (forehead positive), 6.0 msec (forehead negative) and 8.4 msec (forehead positive; bandpass: 200-2000 Hz; average of 1024 trials), had amplitudes of about 0.5 microV. The middle latency responses had peaks at about 8.8 msec (forehead positive), 18.8 msec (forehead negative) and 26.8 msec (forehead positive; 30-300 Hz; N = 128 trials), with larger amplitudes (about 15 microV). These responses were consistently recorded in the same subject at different times and were similar in different normal subjects. Strenuous control experiments were conducted in order to ensure that these responses are not artefacts due to the movement of conducting media (head, electrodes and leads) in the electromagnetic field of the motor and are elicited by activation of normal labyrinths.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献