全文获取类型
收费全文 | 2798篇 |
免费 | 264篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 63篇 |
妇产科学 | 65篇 |
基础医学 | 363篇 |
口腔科学 | 58篇 |
临床医学 | 355篇 |
内科学 | 708篇 |
皮肤病学 | 30篇 |
神经病学 | 147篇 |
特种医学 | 116篇 |
外科学 | 428篇 |
综合类 | 53篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 180篇 |
眼科学 | 74篇 |
药学 | 184篇 |
中国医学 | 13篇 |
肿瘤学 | 238篇 |
出版年
2023年 | 21篇 |
2022年 | 60篇 |
2021年 | 113篇 |
2020年 | 78篇 |
2019年 | 90篇 |
2018年 | 91篇 |
2017年 | 62篇 |
2016年 | 63篇 |
2015年 | 90篇 |
2014年 | 112篇 |
2013年 | 149篇 |
2012年 | 159篇 |
2011年 | 192篇 |
2010年 | 128篇 |
2009年 | 107篇 |
2008年 | 137篇 |
2007年 | 141篇 |
2006年 | 162篇 |
2005年 | 141篇 |
2004年 | 126篇 |
2003年 | 108篇 |
2002年 | 104篇 |
2001年 | 87篇 |
2000年 | 61篇 |
1999年 | 42篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1994年 | 14篇 |
1992年 | 29篇 |
1991年 | 39篇 |
1990年 | 25篇 |
1989年 | 30篇 |
1988年 | 26篇 |
1987年 | 29篇 |
1986年 | 19篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1972年 | 8篇 |
1971年 | 10篇 |
1969年 | 8篇 |
排序方式: 共有3093条查询结果,搜索用时 10 毫秒
1.
We compared the effects of alpha 2- and beta-adrenoreceptor blockade on the central actions of catecholamines and metabolites of alpha-methyldihydroxyphenylalanine, epinephrine, alpha-methylnorepinephrine, and alpha-methylepinephrine were studied. I.c.v. and nucleus tractus solitarii (NTS) injections were carried out under anesthesia. Following i.c.v. injection, both epinephrine and methylepinephrine rapidly reduced blood pressure and heart rate, but the effects of methylnorepinephrine occurred somewhat later. Following microinjection into the nucleus of the solitary tract, epinephrine, methylepinephrine, and methylnorepinephrine all caused hypotension and bradycardia. The hypotensive effects of all 3 amines in the NTS were attenuated in additive fashion by yohimbine, an alpha 2 adrenoreceptor antagonist, and timolol, a beta-adrenoreceptor antagonist, whereas only yohimbine attenuated the bradycardia. The combination of yohimbine and timolol abolished the effects of the amines. These data suggest that in the NTS both alpha 2 and beta adrenoreceptor stimulation contribute to the hypotensive effects of these amines, but that only alpha 2 adrenoreceptors are principally involved in the heart rate response. 相似文献
2.
Therapy of human cervical carcinoma with monoclonal antibody-Pseudomonas exotoxin conjugates. 总被引:1,自引:0,他引:1
Pseudomonas exotoxin A (PE) linked to the F(ab')2 fragment of 1H10, a murine monoclonal antibody recognizing a carbohydrate epitope of a glycoconjugate expressed on the surface of human cervical carcinoma tumor cells, was evaluated for in vitro and in vivo activity. PE can kill cells by ADP-ribosylating elongation factor 2 thus inhibiting protein synthesis. Disulfide- as well as thioether-linked immunotoxins (1H10-PE) killed cervical carcinoma cells in vitro and were 20-160 times more inhibitory to target than to control cells. Cell killing was antibody mediated as demonstrated by the reduction of 1H10-PE growth inhibition to target CaSki cells by free 1H10 F(ab')2. In addition, a control antibody immunotoxin was nontoxic to CaSki cells. Thioether-linked 1H10-PE administered either i.v. or i.p. suppressed the growth of established solid s.c. cervical carcinoma tumors xenografted in nude mice for over 30 days. Treatment with antibody alone or a control immunotoxin had no significant effect on tumor growth. Administration of immunotoxin i.p. was associated with less toxicity than administration i.v., but i.v. injections were more effective at suppressing the growth of established solid tumors. 相似文献
3.
4.
J T Tung P J Venta J P Caron 《Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society》2002,10(1):5-12
OBJECTIVE: To determine the effects of recombinant equine IL-1beta and a number of antiinflammatory compounds on the expression and activity of inducible nitric oxide synthase (iNOS) in cultured equine chondrocytes. DESIGN: RT-PCR methods were used to amplify a portion of the equine iNOS message to prepare an RNA probe. Northern blot analysis was used to quantify the expression of iNOS in first passage cultures of equine articular chondrocytes propagated in the presence or absence of recombinant equine interleukin-1beta (reIL-1beta), dexamethasone (DEX), polysulfated glycosaminoglycan (PSGAG), hyaluronan (HA), and phenylbutazone (PBZ), each at concentrations of 10 and 100 microg/ml. Nitrite concentrations in conditioned media of similarly treated cells were used to quantify iNOS activity. RESULTS: Recombinant equine IL-1beta increased the expression of iNOS in a dose-dependent manner. This result was paralleled by an increased concentration of nitrite in the culture media of reIL-1beta-treated cells. DEX and PSGAG significantly reduced iNOS gene expression and media supernatant nitrite concentrations in cytokine-stimulated cultures. HA and PBZ had no consistent effect on the expression of iNOS and did not significantly influence nitrite content of conditioned media. CONCLUSIONS: NO is considered an important mediator in the pathophysiologic processes of arthritis and an inducible NOS is expressed by equine chondrocytes. Pre-translational regulation of the iNOS gene by DEX and PSGAG appears to contribute to the cartilage-sparing properties of these compounds. 相似文献
5.
J. W. G. Tiller K. P. Maguire B. M. Davies J. T. Dowling L. H. Tung M. J. Rand 《Human psychopharmacology》1990,5(4):313-321
Five out of 12 physically healthy patients with depression undergoing a tyramine pressor test developed cardiac arrhythmias. These arrhythmias occurred in drug-free patients in three out of 12 infusions following as little as 0.03 mg/kg of tyramine and after moclobemide, a reversible inhibitor of monoamine oxidase-A, in four out of 14 tyramine infusions with as little as 0.04 mg/kg of tyramine. The arrhythmias seen were independent of patient's age and occurred both before and after 30 mmHg elevations in systolic blood pressure. Electrocardiographic abnormalities and arrhythmias seen were a loss of p waves, sinus tachycardia, frequent atrial ectopic beats, atrial premature beats, Wenckebach phenomenon, junctional rhythm, ventricular ectopics, varying QRS configurations, and ventricular bigeminy. Tyramine, both oral and intravenous, caused similar reproducible changes in dogs, though not in rats, mice or guinea pigs. Practical implications are that tyramine pressor testing in humans should be performed cautiously and only with adequate cardiac monitoring and resuscitation facilities at hand. These findings suggest that a normal dietary component can induce serious cardiac arrhythmias, and that a low-tyramine diet may be of value for patients who are susceptible to cardiac arrhythmias. 相似文献
6.
F Y Hsu C J Tung J C Chen Y L Wang H C Huang R G Zamenhof 《Applied radiation and isotopes》2004,61(5):881-885
In 1998, an epithermal neutron test beam was designed and constructed at the Tsing Hua Open-Pool Reactor (THOR) for the purpose of preliminary dosimetric experiments in boron neutron capture therapy (BNCT). A new epithermal neutron beam was designed at this facility, and is currently under construction, with clinical trials targeted in late 2004. Depth dose-rate distributions for the THOR BNCT test beam have been measured by means of activation foil and dual ion chamber techniques. Neutron and structure-induced gamma spectra measured at the test beam exit were configured into a source function for the Monte Carlo-based treatment planning code NCTPlan. Dose-rate scaling factors (DRSFs) were determined to normalize computationally derived dose-rate distributions with experimental measurements in corresponding mathematical and physical phantoms, and to thus enable accurate treatment planning using the NCTPlan code. A similar approach will be implemented in characterizing the new THOR epithermal beam in preparation for clinical studies. This paper reports the in-phantom calculated and experimental dosimetry comparisons and derived DRSFs obtained with the THOR test beam. 相似文献
7.
Calcium antagonists inhibit positive chronotropic responses to alpha 1-adrenoceptor activation in rat isolated atria 总被引:1,自引:0,他引:1
Positive chronotropic responses of rat isolated atria to phenylephrine were reduced by propranolol (0.3 microM) and the residual response was further depressed by the selective alpha 1-adrenoceptor antagonist prazosin (1 nM) but not yohimbine (10 nM), confirming that a component of the response to phenylephrine was due to activation of alpha 1-adrenoceptors. When beta-adrenoceptors were blocked by propranolol, the positive chronotropic response to phenylephrine was enhanced by increasing the calcium concentration and by the calcium channel activator Bay K 8644 (0.1 microM), whereas the response was decreased by lowering the calcium concentration and by the calcium antagonists verapamil (10 nM), nifedipine (10 nM) and diltiazem (100 nM). In the presence of prazosin, when phenylephrine acts only on beta-adrenoceptors, calcium antagonists had no effect on the response. In rat isolated aortic strips in a calcium-free, high K+ (40 mM) solution, verapamil (10 nM), nifedipine (10 nM) and diltiazem (100 nM) shifted the calcium-induced contraction curves to the right, but prazosin (10 nM) had no effect, indicating that it is not a calcium antagonist. The calcium antagonists in the concentrations stated above had no effect on phenylephrine-induced contractions of rat aortic strips in normal Krebs-Henseleit solution, indicating that they did not block alpha 1-adrenoceptors in these concentrations. Taken together, these data suggest that the positive chronotropic effect of phenylephrine resulting from activation of alpha 1-adrenoceptors involves an increased influx of calcium through channels that are sensitive to organic calcium antagonists. 相似文献
8.
The mental health problems of the Vietnamese in Calgary: major aspects and implications for service.
N P Tung 《Canada's mental health》1986,34(4):5-9
Since 1975 Indo-Chinese refugees have come to Canada in many waves. They left wartorn motherlands where the society was predominantly agricultural and the traditional culture valued family relationships, spiritual equilibrium, harmony and simplicity. The new lands in which these refugees are seeking to re-establish their lives are highly industrialized, competitive and multi-cultural, and, moreover, base their communications on a very different language. In making such major re-adjustments in their way of life, it is inevitable that there be some failures and even casualties. This paper describes mental health problems as perceived by Vietnamese immigrants in Calgary. It is hoped that this small piece of work will help to promote the mutual understanding necessary for the successful integration of the Indo-Chinese refugees in general and the Vietnamese in particular into the mainstream of Canadian society. 相似文献
9.
Retrospective analysis of 5037 patients with nasopharyngeal carcinoma treated during 1976-1985: overall survival and patterns of failure. 总被引:33,自引:0,他引:33
A W Lee Y F Poon W Foo S C Law F K Cheung D K Chan S Y Tung M Thaw J H Ho 《International journal of radiation oncology, biology, physics》1992,23(2):261-270
This is a retrospective analysis of 5037 patients with squamous cell carcinoma of the nasopharynx treated during the years 1976-1985. The stage distribution according to Ho's classification was 9% Stage I, 13% II, 50% III, 22% IV, and 6% Stage V. Only 4488 (89%) patients had a full course of megavoltage radiation therapy. The median equivalent dose to the nasopharyngeal region was 65 Gy and cervical region in node-positive patients 53 Gy. Seventy percent (906/1290) of the node-negative patients had no prophylactic neck irradiation. The overall actuarial 10-year survival rate was 43%, and the corresponding failure-free survival 34%. Altogether, 4157 (83%) patients achieved complete remission lasting more than 6 months, but 53% (2205/4157) of them relapsed after a median interval of 1.4 years. The 10-year actuarial local, regional, and distant failure-free rates were 61%, 64%, and 59%, respectively. Thirty-eight percent (338/891) of all patients with local recurrence achieved second local remission. The local complete remission rate with aggressive re-irradiation alone was 47% (333/706). But 37% (124/338) of the responders recurred the second time. The incidence of distant failure correlated significantly with both the N-stage and the T-stage, with the highest (57%) occurring in patients with N3 disease. The incidence of nodal relapse in node-negative patients was 11% (44/384) among those given prophylactic neck irradiation, but 40% (362/906) among those without. Therapeutic irradiation achieved a complete regional remission rate of 90% (306/339). However, despite successful salvage, these patients had a significantly higher distant failure rate than those without nodal relapse, even if they remained local-failure-free (21% vs 6%). Patients treated during 1981-1985 achieved significantly better treatment results than those treated during 1976-1980, especially in terms of the overall survival (57% vs 47% at 5-year), the overall failure-free survival (42% vs 35% at 5-year), and the local failure-free rate (70% vs 63% at 5-year). The possible contributing factors are discussed. 相似文献
10.
Renal transplant obstruction by B cell lymphoproliferative disorder: case report and review of the literature 总被引:1,自引:0,他引:1
L J Gibel A Harford L R Yogel J Spiegel W Sterling K Tung 《The Journal of urology》1988,140(3):593-595
We report a case of renal transplant ureteral obstruction caused by a cyclosporine-associated B cell lymphoproliferative disorder. The interaction of cyclosporine with Epstein-Barr virus infections and the predisposition towards B cell lymphoproliferative disorders are reviewed. The characterization of these tumors by deoxyribonucleic acid hybridization studies and a review of the clinical experience treating these disorders also are presented. 相似文献