全文获取类型
收费全文 | 2146236篇 |
免费 | 162539篇 |
国内免费 | 7895篇 |
专业分类
耳鼻咽喉 | 28832篇 |
儿科学 | 69090篇 |
妇产科学 | 59122篇 |
基础医学 | 297666篇 |
口腔科学 | 60042篇 |
临床医学 | 186710篇 |
内科学 | 439354篇 |
皮肤病学 | 50014篇 |
神经病学 | 174428篇 |
特种医学 | 85770篇 |
外国民族医学 | 597篇 |
外科学 | 332646篇 |
综合类 | 47516篇 |
现状与发展 | 2篇 |
一般理论 | 664篇 |
预防医学 | 169198篇 |
眼科学 | 47071篇 |
药学 | 152060篇 |
5篇 | |
中国医学 | 4160篇 |
肿瘤学 | 111723篇 |
出版年
2018年 | 24399篇 |
2017年 | 18478篇 |
2016年 | 20640篇 |
2015年 | 23260篇 |
2014年 | 32275篇 |
2013年 | 48970篇 |
2012年 | 64078篇 |
2011年 | 68415篇 |
2010年 | 41523篇 |
2009年 | 39127篇 |
2008年 | 63438篇 |
2007年 | 67769篇 |
2006年 | 68209篇 |
2005年 | 66539篇 |
2004年 | 63086篇 |
2003年 | 61092篇 |
2002年 | 58776篇 |
2001年 | 98694篇 |
2000年 | 101905篇 |
1999年 | 85474篇 |
1998年 | 24851篇 |
1997年 | 22325篇 |
1996年 | 23019篇 |
1995年 | 22590篇 |
1994年 | 21230篇 |
1993年 | 19851篇 |
1992年 | 68946篇 |
1991年 | 66565篇 |
1990年 | 64481篇 |
1989年 | 61521篇 |
1988年 | 57067篇 |
1987年 | 56035篇 |
1986年 | 53310篇 |
1985年 | 51172篇 |
1984年 | 38838篇 |
1983年 | 32809篇 |
1982年 | 20257篇 |
1981年 | 18017篇 |
1980年 | 17064篇 |
1979年 | 35266篇 |
1978年 | 25264篇 |
1977年 | 21326篇 |
1976年 | 19802篇 |
1975年 | 21149篇 |
1974年 | 25050篇 |
1973年 | 23958篇 |
1972年 | 22444篇 |
1971年 | 20714篇 |
1970年 | 19227篇 |
1969年 | 18123篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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
992.
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
993.
Because of the trend toward a marked decrease in length of psychiatric hospitalization, clinicians need to improve the organization of the therapeutic milieu so that behavioral changes can be effected more rapidly. A university general psychiatric unit has adapted a problem-solving model that integrates groups and activities so that each one focuses on complementary behavioral objectives for each patient with the aim of effecting more rapid behavior change. The stages of the model are incorporated in a weekly sequence that begins with a goal-setting group. In a series of subsequent groups, each patient tries to develop and implement a solution to the problem identified that week. At the end of each week, patients participate in a goal review group, with feedback from staff and peers and self-reinforcement. The model can be used with a diverse patient population without interfering with each patient's individual psychotherapy or pharmacotherapy. 相似文献
994.
995.
A Hugoson G Koch T Bergendal A L Hallonsten L Laurell D Lundgren J E Nyman 《Swedish dental journal》1986,10(3):103-117
The aim of the present study was to present data from dental care habits and knowledge of oral health in two cross-sectional studies carried out in 1973 and 1983. A random sample of approximately 1000 individuals evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60 and 70 years was studied for each of these two years. In the 1983-year examination 80 individuals 80 years of age were also included. All subjects were inhabitants of the community of J?nk?ping, Sweden. A questionnaire about dental care habits and knowledge was used in combination with a clinical and radiographical examination. The participants answered 23-101 questions. The same questions were raised in 1973 and 1983. For most age groups more then 80 per cent visited a dentist yearly in 1983. This yearly attendance was higher than that for 1973. In the 20-year-old group 14 per cent of the individuals received dental care in the PDS in 1973 compared to 63 per cent in 1983. The main reason to visit a dentist in 1973 was by the patient's own initiative while in 1983 the appointments were based on the dentist's initiative. The number of subjects that felt discomfort in connection with a visit to the dentist had decreased between 1973 and 1983. Knowledge about the etiology of caries had increased between 1973 and 1983 was not the case for gingivitis and periodontitis. An increase had occurred in toothbrushing frequency and the use of toothpicks and disclosing tablets but this between 1973 and 1983. In 1983, 98 to 93 per cent of the subjects in the age groups 10-30 years had been exposed to topical fluorides. The corresponding figure for 30-year-olds in 1973 was 1 per cent. It is obvious that during the period 1973 to 1983 there has been an increase in dental attendance, knowledge of dental diseases, oral health and the use of preventive measures. 相似文献
996.
Rapid, competitive enzymoimmunoassay for albumin in urine 总被引:1,自引:0,他引:1
In this solid-phase competitive enzymoimmunoassay for albumin in human urine, antiserum to human serum albumin labeled with horseradish peroxidase (EC 1.11.1.7) is incubated with solid-phase-bound human serum albumin in the presence of sample or standard. Results obtained correlate well (r = 0.96) with those of an established fluoroimmunoassay. The present assay covers the range 0.9 to 200 mg/L and can be performed within 1 h. These characteristics, together with the simplicity of the assay protocol, make it very useful for monitoring low concentrations of albumin in urine. Detection of such minimal albuminuria allows initiation of therapy that may prevent development of clinical proteinuria and associated diabetic nephropathy. 相似文献
997.
998.
999.
1000.
Increased production of peroxidation products associated with cardiac operations. Evidence for free radical generation 总被引:7,自引:0,他引:7
D Royston J S Fleming J B Desai S Westaby K M Taylor 《The Journal of thoracic and cardiovascular surgery》1986,91(5):759-766
We investigated the degree and time course of neutrophil sequestration into human lungs during cardiac operations. At the same time, measurement of the concentration of peroxidation products in the plasma was used as an index of oxidant free radical activity. The study was performed in two groups of patients. Group A (n = 11) had studies extending over the entire operative period and showed a highly significant sequestration of neutrophils into the lung, together with a highly significant (p less than 0.001) rise in peroxidation products from 2.8 +/- 0.12 nmol/ml(mean +/- standard error of the mean)before bypass to a peak of 5.05 +/- 0.13 nmol/ml at the end of bypass. As these changes occurred only during the time after release of the aortic cross-clamp, we investigated this period in more detail in a second group of patients (Group B, n = 7). Results from this group showed that significant release of peroxidation products occurred at the same time as pulmonary neutrophil sequestration. This study has produced evidence of increased oxidant activity in the lung associated with cardiac operations. Nevertheless, it is not known whether the neutrophils sequestered into the lung alone induced the increased activity. Similarly, whether neutrophil-derived oxidant species are the sole cause of lung tissue injury remains unproved. 相似文献