全文获取类型
收费全文 | 3438篇 |
免费 | 232篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 60篇 |
妇产科学 | 34篇 |
基础医学 | 484篇 |
口腔科学 | 49篇 |
临床医学 | 365篇 |
内科学 | 871篇 |
皮肤病学 | 177篇 |
神经病学 | 310篇 |
特种医学 | 136篇 |
外科学 | 479篇 |
综合类 | 21篇 |
一般理论 | 3篇 |
预防医学 | 229篇 |
眼科学 | 61篇 |
药学 | 169篇 |
中国医学 | 2篇 |
肿瘤学 | 218篇 |
出版年
2023年 | 25篇 |
2022年 | 31篇 |
2021年 | 106篇 |
2020年 | 55篇 |
2019年 | 73篇 |
2018年 | 97篇 |
2017年 | 84篇 |
2016年 | 79篇 |
2015年 | 86篇 |
2014年 | 138篇 |
2013年 | 160篇 |
2012年 | 247篇 |
2011年 | 286篇 |
2010年 | 156篇 |
2009年 | 147篇 |
2008年 | 224篇 |
2007年 | 268篇 |
2006年 | 198篇 |
2005年 | 184篇 |
2004年 | 180篇 |
2003年 | 135篇 |
2002年 | 128篇 |
2001年 | 27篇 |
2000年 | 24篇 |
1999年 | 21篇 |
1998年 | 48篇 |
1997年 | 34篇 |
1996年 | 48篇 |
1995年 | 33篇 |
1994年 | 34篇 |
1993年 | 20篇 |
1992年 | 15篇 |
1991年 | 23篇 |
1990年 | 30篇 |
1989年 | 42篇 |
1988年 | 27篇 |
1987年 | 31篇 |
1986年 | 33篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 9篇 |
1974年 | 6篇 |
1973年 | 3篇 |
排序方式: 共有3699条查询结果,搜索用时 46 毫秒
1.
2.
Ittel TH; Steinhausen C; Kislinger G; Kinzel S; Nolte E; Sieberth HG 《Nephrology, dialysis, transplantation》1997,12(7):1369-1375
BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit
the determination of femtogram amounts of 26Al in blood and in various
tissues with good precision and free of external contamination. METHODS: In
the present study we used trace quantities of 26Al to investigate the
intestinal absorption and compartmentalization of aluminium in rats with
renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single
oral doses of 20 ng 26Al were administered to six animals in each group
and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone,
liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al
were significantly lower in uraemic rats compared to controls, whereas
urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/-
6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in
uraemia. The target tissues of cellular transferrin-mediated 26Al uptake,
liver and spleen, tended to show a larger degree of aluminium accumulation
in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27
pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site
of extracellular aluminium deposition, 26Al concentrations were more
elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g).
Estimated total 26Al accumulation in all measured target tissues was
significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/-
7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/-
6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a
fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our
data suggest that fractional absorption from a dietary level dose of 26Al
is about 0.13%. Compartmentalization occurs in transferrin-dependent target
tissues such as liver and spleen; however, in quantitative terms
extracellular deposition in bone is more important. Uraemia has a
significant effect on the intestinal absorption and compartmentalization of
aluminium. It enhances fractional absorption and increases subsequent
extracellular deposition of aluminium in bone. However, at the same time
uraemia does not increase transferrin-dependent cellular accumulation of
aluminium in liver and spleen.
相似文献
3.
H Jacobus Gilhuis Carien H G Beurskens Joost de Vries Henri A M Marres Ed H M Hartman Machiel J Zwarts 《Journal of clinical neurophysiology》2003,20(2):151-154
The purpose of this study was to analyze contralateral reinnervation of the facial nerve in eight patients with complete facial palsy after surgery or trauma and seven healthy volunteers. All patients had contralateral reinnervation of facial muscles as demonstrated by electrical nerve stimulation versus none of the control subjects. Four patients had facial muscle movements at the site of the damaged nerve. In one patient this was entirely the result of contralateral reinnervation, whereas the other three patients had innervation both ipsilaterally and contralaterally. This implies that renewed facial muscle activity should be examined considering the origin of the reinnervation, either contralateral or ipsilateral. Contralateral reinnervation is a common phenomenon after total facial palsy and can occur alongside ipsilateral reinnervation. It can be mistaken for adequate reinnervation of the damaged nerve, causing postponement of dynamic reconstruction therapy. 相似文献
4.
Nicole Y. L. Oei Bernet M. Elzinga Oliver T. Wolf Michiel B. de Ruiter Jessica S. Damoiseaux Joost P. A. Kuijer Dick J. Veltman Philip Scheltens Serge A. R. B. Rombouts 《Brain imaging and behavior》2007,1(1-2):31-41
Glucocorticoids (GCs, cortisol in human) are associated with impairments in declarative memory retrieval. Brain regions hypothesized
to mediate these effects are the hippocampus and prefrontal cortex (PFC). Our aim was to use fMRI in localizing the effects
of GCs during declarative memory retrieval. Therefore, we tested memory retrieval in 21 young healthy males in a randomized
placebo-controlled crossover design. Participants encoded word lists containing neutral and emotional words 1 h prior to ingestion
of 20 mg hydrocortisone. Memory retrieval was tested using an old/new recognition paradigm in a rapid event-related design.
It was found that hydrocortisone decreased brain activity in both the hippocampus and PFC during successful retrieval of neutral
words. These observations are consistent with previous animal and human studies suggesting that glucocorticoids modulate both
hippocampal and prefrontal brain regions that are crucially involved in memory processing.
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
Summary Sodium fluoride 10, 20, or 40 mg/kg body weight was given intraperitoneally to rats (6–11 days old and 90–95 days old). Blood
analyses showed an initial increase in plasma fluoride concentration. The subsequent decrease in fluoride was paralleled by
a decrease in total plasma calcium. These plasma concentrations were normal at blood collection 4 days after fluoride injection.
The baby rats differed from the older rats in that their initial plasma calcium was higher and that the drop in plasma calcium
concentration was less pronounced than in the old rats. A diet low in calcium and phosphate enhanced the effects of fluoride
on total plasma calcium. The data indicate that the effect of large doses of fluoride on lowering the plasma calcium level
is modified by the calcium intake. 相似文献
6.
Joost Doornbos Peter R. Luyten Matthijs Janssen Martin Wasser Albert De Roos 《Journal of magnetic resonance imaging : JMRI》1994,4(2):165-168
Three-dimensionally localized proton-decoupled phosphorus-31 magnetic resonance (MR) spectroscopy of skeletal and cardiac muscle was performed in six patients with systemic sclerosis. Cardiac (n = 9) and skeletal (n = 6) spectra were also obtained in healthy volunteers. Metabolite ratios and intracellular pH were determined from the spectra of skeletal and cardiac muscle. The phosphocreatine-to-adenosine triphosphate ratio was normal for both skeletal and cardiac muscle in patients with systemic sclerosis. The pH values of skeletal muscle were similar in patients and control subjects (7.13 ± 0.02 vs 7.12 ± 0.01, respectively). In skeletal muscle, the inorganic phosphate-to-phosphocreatine ratio in patients was increased relative to that of control subjects (0.106 ± 0.014 vs 0.086 ± 0.006, respectively; P =.02). P-31 MR spectroscopy showed no abnormalities in the myocardium of patients with systemic sclerosis. Assessment of the inorganic phosphate-to-phosphocreatine ratio in peripheral skeletal muscle may be helpful for assessing disease activity. 相似文献
7.
J. D. R. Peereboom-Wynia Th. van Joost E. Stolz M. E. F. Prins 《Journal of cutaneous pathology》1986,13(5):363-369
In a selected group of 8 patients with progressive alopecia areata (AA) leading to AA universalis, immunological aspects (in the peripheral blood and the tissue) were studied during the period of the intitial attack of the disease. The peripheral T-cell helper/suppressor ratio appeared not to be a reliable parameter for the disease activity. The intrabulbar and peribulbar distribution of T-cells, Langerhans cells and of HLA-DR expression in and around the anagen hair follicles in the progressive areas of the disease (region of exclamation-mark hairs) may suggest a T-cell-mediated injury primarily in the peribulbar regions of the follicles. The data presented tend to support the possibility that in the early development of AA, the dermal pailla (capillary network?) may be the prime target of immunologic injury. 相似文献
8.
Objective: Accidental injury of tissues during CO2 laser irradiation can lead to serious morbidity, especially during ear, nose, and throat, neurosurgical, and plastic-reconstructive procedures. This experimental study describes a new technique in which vital structures are coated with a thin layer of fibrin glue to protect them from accidental CO2 laser irradiation. Study Design/Materials and Methods: The femoral neurovascular bundles (femoral artery, vein, and nerve) of 12 rats were exposed. On one side the bundle was coated with fibrin glue, which is a biological two-component glue consisting of fibrinogen solution and thrombin. Upon application, an elastic mass on the neurovascular bundle was formed. The contralateral neurovascular bundle was left uncoated. Subsequently both bundles were subjected to CO2 laser irradiation at different powers (5, 7, and 9 W), with an irradiation time of 0.1 seconds. Light microscopy was performed at 30 minutes and 2 days after surgery. Results: No macroscopic visible hemorrhages occurred during laser irradiation in the glue-coated bundle. Light microscopic evaluation revealed an undamaged neurovascular bundle without any signs of thermal damage. In the uncoated bundles intraoperative hemorrhages resulting from laser energy occurred in all specimens. Furthermore, severe thermal damage was present in arteries, veins, and nerves. Conclusions: Intraoperative coating with fibrin glue can serve as a shield to protect vital structures such as arteries, veins, and nerves from accidental CO2 laser exposure. Key Words: Arteries, CO2 laser, fibrin glue, peripheral nerve, veins. 相似文献
9.
The combination of a surgical and adhesive restorative approach to treat a deep crown-root fracture: a case report. 总被引:1,自引:0,他引:1
Most dental trauma requires immediate action to preserve the affected teeth. Furthermore, the trauma has often a great impact on the appearance and well being of the patient. In this case trauma resulted in a very deep complicated crown-root fracture of one incisor and a complicated crown fracture in another incisor of a 47-year-old woman. A combination of surgical extrusion and adhesive restoration was chosen to provide good prognosis for the teeth as well as an instant esthetic result that was well accepted by the patient. Eleven months after trauma, the treated teeth exhibited good healing and normal function. 相似文献
10.
Joost B. M. M. van Bree Anne V. Baljet Anton van Geyt Albertus G. de Boer Meindert Danhof Douwe D. Breimer 《Journal of pharmacokinetics and pharmacodynamics》1989,17(4):441-462
The unit impulse response theory has been adapted to characterize the transport profile of drugs into the central nervous system (CNS). From the obtained input function, the cumulative plasma volume (V) cleared by transport into the CNS in time can be calculated. Simulation studies demonstrated that transport governed by passive diffusion resulted in a linear relationship between V and time, while the slope of the line, the blood- brain barrier (BBB) clearance, proved to be an adequate and model independent parameter to characterize drug transport into the CNS. The error in the result of the numerical procedure could be limited to less than 10% of the theoretically predicted value. Superposition of 5 or 10% random noise on simulated data did not result in significant differences between the calculated and theoretically predicted clearance values. Simulations of carrier-mediated transport resulted in nonlinear transport curves; the degree of nonlinearity, and thus the detectability, was dependent on the initial degree of saturation of the system, the rate of desaturation, as caused by drug elimination processes and the noise level on the data. In vivoexperiments in the rat were performed, using atenolol, acetaminophen, and antipyrine as model drugs. Linear transport relationships were obtained for all drugs, indicating that transport was dependent on passive diffusion or a low affinity carrier system. BBB- clearance values were 7±1 l/min for atenolol, 63±7 ul/min for acetaminiphen and 316±25 l/min for antipyrine. These experiments validate the applicability of the presented technique in in vivostudies. 相似文献