全文获取类型
收费全文 | 29357篇 |
免费 | 1539篇 |
国内免费 | 93篇 |
专业分类
耳鼻咽喉 | 359篇 |
儿科学 | 1025篇 |
妇产科学 | 871篇 |
基础医学 | 4002篇 |
口腔科学 | 897篇 |
临床医学 | 2750篇 |
内科学 | 6271篇 |
皮肤病学 | 607篇 |
神经病学 | 2776篇 |
特种医学 | 962篇 |
外科学 | 3701篇 |
综合类 | 158篇 |
一般理论 | 9篇 |
预防医学 | 2295篇 |
眼科学 | 610篇 |
药学 | 2084篇 |
中国医学 | 90篇 |
肿瘤学 | 1522篇 |
出版年
2023年 | 232篇 |
2022年 | 339篇 |
2021年 | 766篇 |
2020年 | 462篇 |
2019年 | 626篇 |
2018年 | 877篇 |
2017年 | 682篇 |
2016年 | 726篇 |
2015年 | 749篇 |
2014年 | 973篇 |
2013年 | 1365篇 |
2012年 | 2011篇 |
2011年 | 1998篇 |
2010年 | 1033篇 |
2009年 | 950篇 |
2008年 | 1642篇 |
2007年 | 1760篇 |
2006年 | 1695篇 |
2005年 | 1758篇 |
2004年 | 1583篇 |
2003年 | 1580篇 |
2002年 | 1500篇 |
2001年 | 609篇 |
2000年 | 592篇 |
1999年 | 514篇 |
1998年 | 202篇 |
1997年 | 153篇 |
1996年 | 149篇 |
1995年 | 141篇 |
1994年 | 131篇 |
1993年 | 99篇 |
1992年 | 283篇 |
1991年 | 244篇 |
1990年 | 201篇 |
1989年 | 226篇 |
1988年 | 172篇 |
1987年 | 193篇 |
1986年 | 177篇 |
1985年 | 164篇 |
1984年 | 98篇 |
1983年 | 85篇 |
1982年 | 66篇 |
1981年 | 63篇 |
1979年 | 108篇 |
1978年 | 70篇 |
1977年 | 81篇 |
1975年 | 69篇 |
1974年 | 76篇 |
1973年 | 63篇 |
1972年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
A new monoclonal antibody against the GABA-protein conjugate shows immunoreactivity in sensory neurons of the rat. 总被引:5,自引:0,他引:5
A monoclonal antibody, 115AD5, was raised against GABA coupled to bovine serum albumin. The monoclonal antibody 115AD5 also reacted with other GABA-protein conjugates. The specificity of the monoclonal antibody was corroborated by enzyme-linked immunoassay, dot-immunobinding experiments and immunostaining of rat cerebellum sections. The monoclonal antibody 115AD5 could successfully be applied on Vibratome and cryostat sections using either indirect immunofluorescence or peroxidase techniques. In rat cerebellar cortex the monoclonal antibody 115AD5 gave an intense immunoreaction in stellate cells, in Golgi neurons, and in basket cells and their processes around Purkinje cell bodies. Purkinje cell dendrites showed GABA immunoreactivity while the cell bodies were non-reactive or only weakly reactive. There was labelling in some nuclei of Purkinje cells. GABA immunoreactivity was also found in dot-like structures in the granular layer. A large population of sensory neurons in rat thoracic and lumbar spinal dorsal root ganglia presented an intense immunoreactivity for the monoclonal antibody 115AD5. Nerve bundles immunoreactive for GABA were also seen in these ganglia. In the trigeminal ganglion, a major population of sensory neurons and some of their processes presented immunoreactivity for GABA. In the sensory nodose ganglion of the vagus nerve, many neuronal cell bodies and some fibres were immunoreactive for GABA. Ligation of the vagus nerve caudal to the ganglion resulted in an increased GABA immunoreactivity in neuronal somata of the ganglion, as well as in nerve fibres on the ganglionic side of the ligature. The present results suggest that in the rat, a population of sensory neurons in thoracic and lumbar spinal dorsal root ganglia, as well as in the trigeminal and nodose ganglia contain GABA. The presence of GABA immunoreactivity in these neurons raises the possibility of a neurotransmitter or modulator role. 相似文献
52.
The natural killing of K 562 cells by whole blood from normal subjects was comparable with that shown by separated mononuclear cells. In order to establish the conditions for a reliable natural killer assay by using very small numbers of effector cells in whole blood, the isotope uptake of target cells was increased by a modified labelling method, which permitted the use of fewer target cells in the assay. The natural cytotoxicity of whole blood was augmented by interferon to the same extent as observed with separated mononuclear cells. The chemiluminescence of granulocytes in whole blood comparable with that of separated granulocytes. Taken together, these methods are considerably less tedious than the conventional methods, technique is also economical, and the results may reflect in vivo cytolytic processes much better. 相似文献
53.
M. Guillemin H. Cachier C. Chini D. Dabill D. Dahmann F. Diebold A. Fischer H.-H. Fricke J. A. Groves R. Hebisch M. Houpillart G. Israël M. Mattenklott W. Moldenhauer J. P. Sandino C. Schlums E. Sutter E. Tucek 《International archives of occupational and environmental health》1997,70(3):161-172
<i>Object</i>: Diesel soot has been recognized as probably carcinogenic to humans. Elemental carbon (also called black carbon) in soot
is considered at the moment as the most significant surrogate to be measured for assessing the exposure to this pollutant.
Its analysis is done by combustion in an oven and determination of the CO<sub>2</sub> formed, after elimination of the organic fraction of the soot by heating and/or by solvent extraction. The analysis allows
determination of both fractions of the soot: “elemental carbon” (EC) and organic carbon␣(OC). The sum of EC and OC is called
TC (total carbon). <i>Method</i>: An informal European coordination group organized two round robin tests on filter samples collected from diluted diesel
emissions. The first round (RRT1) was performed on 13 different samples analyzed by ten laboratories. The range of loading
was 2.5 to 150 μg/cm<sup>2</sup> of EC. No evaluation of the precision within laboratories could be made since each laboratory gave only one result per sample.
Therefore a second round (RRT2) was organized with two samples and a blank filter sent in several portions to 11 laboratories.
It should be stressed that each laboratory used its own method and that no standardization was planned at this stage. <i>Results</i>: Results of RRT1 showed that the coefficient of variation between laboratories decreased with higher loading and was around
10% to 15% for EC above about 20 μg/cm<sup>2</sup>. Dispersion of the results varied and it appeared that the way OC is removed from the soot is probably the most important
factor of influence. The correlation between the laboratories was good as a whole but some systematic differences could be
detected. Besides the different techniques to remove the organic carbon, the pretreatment of the filter by HCl (either as
a vapor or as a solution) to remove the inorganic carbonates (potential interference sources), is probably also a significant
factor of influence in the dispersion of the results between laboratories. It is not yet clear from these results whether
the “environmental” laboratories give different results from the “occupational” laboratories, but it is clear that their objectives
differ since for the “environmentalists”, EC is not a specific marker of diesel immissions, in contrast to the “occupationalists”.
<i>Conclusion</i>: It can be concluded that, although significant differences exist between laboratories they can be attributed mainly to the
narrow distribution of the results within a single laboratory, and that the overall agreement of the results for EC and TC
is fairly good. These results obtained with pure diesel engine emissions, should be complemented by field samples, but they
have already achieved relevant findings in the performance of the procedures used to assess exposure to diesel soot.
Received: 30 December 1996 / Accepted: 21 February 1997 相似文献
54.
Automatic assessment of levodopa-induced dyskinesias in daily life by neural networks. 总被引:1,自引:0,他引:1
We developed an objective and automatic procedure to assess the severity of levodopa-induced dyskinesia (LID) in patients with Parkinson's disease during daily life activities. Thirteen patients were continuously monitored in a home-like situation for a period of approximately 2.5 hours. During this time period, the patients performed approximately 35 functional daily life activities. Behavior of the patients was measured using triaxial accelerometers, which were placed at six different positions on the body. A neural network was trained to assess the severity of LID using various variables of the accelerometer signals. Neural network scores were compared with the assessment by physicians, who evaluated the continuously videotaped behavior of the patients off-line. The neural network correctly classified dyskinesia or the absence of dyskinesia in 15-minute intervals in 93.7, 99.7, and 97.0% for the arm, trunk, and leg, respectively. In the few cases of misclassification, the rating by the neural network was in the class next to that indicated by the physicians using the AIMS score (scale 0-4). Analysis of the neural networks revealed several new variables, which are relevant for assessing the severity of LID. The results indicate that the neural network can accurately assess the severity of LID and could distinguish LID from voluntary movements in daily life situations. 相似文献
55.
Herpes simplex virus type 1 infection induces upregulation of interleukin-23 (p19) mRNA expression in trigeminal ganglia of BALB/c mice. 总被引:2,自引:0,他引:2
Eeva K Broberg Niko Set?l? Juha-Pekka Er?linna Aimo A Salmi Matias R?ytt? Veijo Hukkanen 《Journal of interferon & cytokine research》2002,22(6):641-651
We investigated the expression kinetics of several cytokines in trigeminal ganglia (TG) and in brains of BALB/c mice during the course of ocular herpes simplex virus type 1 (HSV-1) infection. All mice recovered from the infection within 2 weeks. The quantitative rapid real-time RT-PCR method was used to analyze interleukin-4 (IL-4), interferon-gamma (IFN-gamma), IL-12p35, IL-12p40, and the recently described IL-23 (p19) mRNA in TG, brain, and splenocyte samples. In TG, we found elevated expression of mRNA for IL-23 (p19) from early acute infection (day 3) to the beginning of the latent phase (day 14). The increase was not detected in brain or in the spleen. IL-4 expression occurred in both TG and brain from the beginning of the experiment to the latent phase. During the latent phase (days 14 and 31), IL-4 expression was significantly elevated in the brain when compared with the uninfected controls (p < 0.05). Considerable expression of IFN-gamma mRNA was detected in TG of mice during acute HSV-1 infection. The expression of IL-23 was detected also in the brains of the mice, even though no significant changes were found during the acute HSV-1 infection. This is, to our knowledge, the first report to show elevated expression of IL-23 (p19) mRNA (p < 0.05) during viral infection in TG of mice. 相似文献
56.
Ilkka Sinisaari Hannu Pätiälä Ole Böstman E. Antero Mäkelä Esa K. Partio Eero Hirvensalo Pertti Törmälä Pentti Rokkanen 《Journal of orthopaedic science》1997,2(2):88-92
Between November 1984 and January 1994 in our department, a total of 2500 patients were treated with totally absorbable internal
fixation devices. We studied these patients and analyzed results with regard to the volume of the absorbable implants and
the development of wound infection. Of the 2500 patients 2044 were trauma patients and 456 were operated on for orthopedic
disease. In 1466 patients treated with implants made of self-reinforced polyglycolic acid (SR-PGA) only, the patients who
developed wound infection had a higher implant volume (<i>P</i>=0.07) than those who did not; this difference was close to statistical significance. In the 446 patients who received only
implants made of self-reinforced poly-<small>l</small>-lactic acid (SR-PLLA), the 5 who developed wound infection had a mean implant volume more than three times that of the non-infected
patients (<i>P</i>=0.01). We found that in the patients treated with the earlier SR-PGA implants, which contained a green staining material,
there was no correlation between implant volume and incidence of wound infections. On the other hand, both the non-stained
SR-PGA implants, which have been in clinical use since 1989, and the SR-PLLA implants, seem to be more predictable in terms
of wound infections. We believe that this difference, is largely due to the lower level of tissue reactions with these newer
implants. 相似文献
57.
Jens Toft Birger Hesse Alan Rabøl Steen Carstensen Samir Ali 《European journal of nuclear medicine and molecular imaging》1997,24(4):409-414
Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise<sup>99m</sup>Tc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of<sup>99m</sup>Tc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in<sup>99m</sup>Tc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary. 相似文献
58.
Chromium supplementation in impaired glucose tolerance of elderly: effects on blood glucose, plasma insulin, C-peptide and lipid levels. 总被引:1,自引:0,他引:1
M I Uusitupa L Mykk?nen O Siitonen M Laakso H Sarlund P Kolehmainen T R?s?nen J Kumpulainen K Py?r?l? 《The British journal of nutrition》1992,68(1):209-216
Altogether twenty-six elderly subjects (aged 65-74 years) with persistent impaired glucose tolerance (World Health Organization (1985) criteria) identified in a population-based study, were randomly treated either with chromium-rich yeast (160 micrograms Cr/d) or with placebo for 6 months. The 24 h urinary Cr increased from 0.13 (SE 0.03) to 0.40 (SE 0.06) micrograms/d in the Cr group (n 13) but no change was found in the placebo group (n 11) (0.13 (SE 0.02) v. 0.11 (SE 0.02) micrograms/d). No significant change was observed in the oral glucose tolerance test (glucose dose 75 g; 0, 1 and 2 h blood glucose respectively): 5.3 (SE 0.1), 9.3 (SE 0.3), 8.2 (SE 0.3) mmol/l v. 5.0 (SE 0.1), 8.5 (SE 0.4), 7.3(SE 0.5) mmol/l in the Cr group; 4.9 (SE 0.2), 9.2 (SE 0.6), 8.1 (SE 0.3) mmol/l v. 4.8 (SE 0.2), 8.5 (SE 0.5), 7.0 (SE 0.6) mmol/l in the placebo group (baseline v. 6 months). Glycosylated haemoglobin, plasma insulin, C-peptide and apolipoprotein A1 and B levels remained unchanged, and no improvement was seen in serum total cholesterol (6.2 (SE 0.3) v. 6.4 (SE 0.3) mmol/l for the Cr group, 6.2 (SE 0.4) v. 6.5 (SE 0.3) mmol/l for the placebo group), high-density-lipoprotein-cholesterol (1.1 (SE 0.1) v. 1.2 (SE 0.1) mmol/l for the Cr group, 1.0 (SE 0.1) v. 1.1 (SE 0.1) mmol/l for the placebo group) or triacylglycerols (2.5 (SE 0.4) v. 2.0 (SE 0.4) mmol/l for the Cr group, 2.4 (SE 0.2) v. 2.5 (SE 0.2) mmol/l for the placebo group). The present results indicate that Cr supplementation does not improve glucose tolerance or serum lipid levels in elderly subjects with stable impaired glucose tolerance. 相似文献
59.
Detectable TNF levels in sera 33% of patients with sepsis following pancreatitis have been found. No correlation was observed between serum TNF concentration and the severity of illness. However, monocytes and granulocytes of septic patients exerted higher TNF-mediated cytotoxicity than leukocytes of normal blood donors. The in vitro TNF-producing capacity was also higher in the patients in the study group, and it decreased only before fatal outcoming of sepsis. Our results suggest that determination of the TNF-producing capacity of leukocytes might be more informative than measurement of the serum TNF level in the evaluation of the severity or prognosis of sepsis. 相似文献
60.
Bartosz Paprota Roman Król Andrzej Wiatrak 《Chirurgia narzadów ruchu i ortopedia polska》2004,69(2):85-89
The authors present the results of hip arthroplasty of 67 patients treated after failed internal fixation of the osteoporotic, trochanteric fractures of the femur, which were primary stabilised with angular plate AO in 39 patients and with dynamic hip screw (DHS) in 28 patients. In the discussed material 16 persons were male and 51 female, in the age between 51 and 83 years old. According to the Evans classification in 4 cases we diagnosed type I of fracture, in 10--type II, 31--type III and in 22--type IV. Hip arthroplasty was made from the 3rd to the 39th week after primary fixation of the fracture. In 42 patients we made total hip arthroplasty, in 14 cases Austin-Moore hemiarthroplasty, and in 11 patients bipolar arthroplasty. According to the Postel and Merle d'Aubigne classification there were obtained 29 very good, 21 good and 17 satisfactory results. 相似文献