全文获取类型
收费全文 | 3368篇 |
免费 | 225篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 49篇 |
妇产科学 | 41篇 |
基础医学 | 468篇 |
口腔科学 | 46篇 |
临床医学 | 331篇 |
内科学 | 825篇 |
皮肤病学 | 176篇 |
神经病学 | 314篇 |
特种医学 | 141篇 |
外科学 | 466篇 |
综合类 | 6篇 |
一般理论 | 3篇 |
预防医学 | 241篇 |
眼科学 | 62篇 |
药学 | 182篇 |
中国医学 | 2篇 |
肿瘤学 | 222篇 |
出版年
2023年 | 25篇 |
2022年 | 31篇 |
2021年 | 104篇 |
2020年 | 56篇 |
2019年 | 71篇 |
2018年 | 97篇 |
2017年 | 83篇 |
2016年 | 78篇 |
2015年 | 82篇 |
2014年 | 134篇 |
2013年 | 160篇 |
2012年 | 252篇 |
2011年 | 287篇 |
2010年 | 152篇 |
2009年 | 142篇 |
2008年 | 224篇 |
2007年 | 253篇 |
2006年 | 195篇 |
2005年 | 184篇 |
2004年 | 180篇 |
2003年 | 133篇 |
2002年 | 126篇 |
2001年 | 25篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 32篇 |
1997年 | 18篇 |
1996年 | 35篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 17篇 |
1992年 | 21篇 |
1991年 | 29篇 |
1990年 | 39篇 |
1989年 | 34篇 |
1988年 | 27篇 |
1987年 | 33篇 |
1986年 | 35篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 4篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1967年 | 4篇 |
排序方式: 共有3604条查询结果,搜索用时 31 毫秒
1.
2.
A de Roos J Doornbos S Rebergen P van Rugge P Pattynama E E van der Wall 《European journal of radiology》1992,14(2):97-103
Recent advances in cardiovascular applications of magnetic resonance (MR) imaging and phosphorus-31 spectroscopy are reported. MR velocity mapping is a valuable adjunct to conventional imaging techniques, providing information on flow velocities as well as on absolute blood flow volume in the aorta and pulmonary arteries. Recently, ultrafast MR techniques have become available to evaluate myocardial perfusion with the aid of MR contrast agents as perfusion marker. Dynamic MR imaging is a powerful tool to assess cardiac function and ventricular mass. In particular, right ventricular function and mass can be evaluated with great accuracy, contributing to improved assessment of the significance of disease processes which may affect the right heart. The role of phosphorus-31 spectroscopy of the heart is expanding for the evaluation of ischemic myocardial disease and cardiomyopathies. The phosphocreatine to adenosine triphosphate ratio appears to be a marker of disease in patients with cardiac hypertrophy. In conclusion, MR imaging and phosphorus-31 spectroscopy is gaining widespread acceptance for evaluation of many cardiovascular disease processes. 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.
H. C. Holscher M.D. H. -J. van der Woude M.D. J. Hermans Ph.D. M. A. Nooy M.D. J. Doornbos Ph.D. J. L. Bloem M.D. 《Skeletal radiology》1994,23(3):181-185
To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor. 相似文献
7.
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
8.
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
9.
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
10.
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