全文获取类型
收费全文 | 6613篇 |
免费 | 384篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 170篇 |
妇产科学 | 147篇 |
基础医学 | 1251篇 |
口腔科学 | 174篇 |
临床医学 | 521篇 |
内科学 | 1144篇 |
皮肤病学 | 196篇 |
神经病学 | 634篇 |
特种医学 | 193篇 |
外科学 | 660篇 |
综合类 | 25篇 |
一般理论 | 2篇 |
预防医学 | 587篇 |
眼科学 | 126篇 |
药学 | 813篇 |
中国医学 | 34篇 |
肿瘤学 | 280篇 |
出版年
2023年 | 74篇 |
2022年 | 78篇 |
2021年 | 154篇 |
2020年 | 120篇 |
2019年 | 172篇 |
2018年 | 294篇 |
2017年 | 201篇 |
2016年 | 238篇 |
2015年 | 212篇 |
2014年 | 342篇 |
2013年 | 496篇 |
2012年 | 668篇 |
2011年 | 732篇 |
2010年 | 405篇 |
2009年 | 196篇 |
2008年 | 248篇 |
2007年 | 264篇 |
2006年 | 238篇 |
2005年 | 175篇 |
2004年 | 166篇 |
2003年 | 146篇 |
2002年 | 139篇 |
2001年 | 55篇 |
2000年 | 41篇 |
1999年 | 49篇 |
1998年 | 64篇 |
1997年 | 53篇 |
1996年 | 46篇 |
1995年 | 52篇 |
1994年 | 39篇 |
1992年 | 32篇 |
1991年 | 30篇 |
1990年 | 35篇 |
1989年 | 25篇 |
1988年 | 27篇 |
1986年 | 25篇 |
1985年 | 31篇 |
1984年 | 31篇 |
1983年 | 22篇 |
1982年 | 39篇 |
1981年 | 28篇 |
1980年 | 29篇 |
1979年 | 25篇 |
1978年 | 23篇 |
1977年 | 28篇 |
1976年 | 28篇 |
1975年 | 28篇 |
1974年 | 22篇 |
1973年 | 24篇 |
1967年 | 24篇 |
排序方式: 共有7021条查询结果,搜索用时 15 毫秒
31.
Highly purified and concentrated interferons obtained from L cells or from mouse peritoneal leukocytes (MPL) after induction with3H-uridin labeled double-stranded RNA of f2 phageE. coli (phage ds-RNA) were analysed by poly-acrylamide gel electrophoresis. A coincidence of the discrete radioactivity peak with one of the interferon activity peaks was demonstrated. 相似文献
32.
33.
CTLA-4 (CD152) gene polymorphism at position 49 in exon 1 in Graves' disease in a Polish population of the Lower Silesian region 总被引:2,自引:0,他引:2
Frydecka I Daroszewski J Suwalska K Zołedziowska M Tutak A Słowik M Potoczek S Dobosz T 《Archivum immunologiae et therapiae experimentalis》2004,52(5):369-374
INTRODUCTION: Graves' disease ((GD)is an autoimmune disease believed to be caused by a combination of environmental and genetic factors. The gene encoding cytotoxic T lymphocyte-associated antigen-4 (CTLA-4)is one of the candidate genes for conferring susceptibility to thyroid autoimmunity. he aim of the study was to investigate the association between the exon 1 CTLA-4 gene polymorphism A(49)G and susceptibility to GD and Graves ' ophthalmopathy (GO)as well as its severity in a Polish population of the Lower Silesia region. MATERIALS AND METHODS: We analyzed the A(49)G exon 1 CTLA-4 gene polymorphism in 99 unrelated Polish patients with GD, of whom 50 had clinically evident GO (NOSPECS class III and higher), and 154 matched healthy subjects from the Lower Silesia region. Genomic DNA was isolated from whole frozen blood using the NucleoSpin Blood kit. A/G transition was genotyped by polymerase chain reaction followed by labeling with the SnaPshot kit of PE Applied Biosystems and detected using an ABI PRISM 310 capillary genetic analyzer. RESULTS: The distribution of CTLA-4 exon 1 A(49)G enotype, allele, and phenotypic frequencies did not differ between patients with GD and healthy subjects. There was a significantly lower frequency of the AA genotype in the group of patients with clinically evident GO than in patients without severe GO (22% vs. 43%; p=0.02, OR=2.6). CONCLUSIONS: Our results showed that the AA genotype in patients with GD is associated with a lower risk of GO severity. 相似文献
34.
Zupanić-Krmek D Nemet D 《Acta medica Croatica : c?asopis Hravatske akademije medicinskih znanosti》2004,58(4):251-261
Opportunistic fungal infections are becoming more frequent complications during cancer therapy, after organ transplantation and in AIDS infections, especially after better control of bacterial infections in immunocompromised patients. Periods of prolonged neutropenia with neutrophil count less than 0.5 x 10(9)/L longer than 7 days, are the most important risk factors for the development of systemic fungal infections. Especially susceptible are the patients during treatment of acute leukemia, or after bone marrow transplantation. The most frequent causing agents of systemic fungal infections are Candida and Aspergillus species, than Cryptococcus neoformans and Mucor. Some other unusual species such Fusarium, Trichosporon, non-albicans Candida species of Candida are becoming more frequent, and is frequently resistant to conventional therapy. The difficulties in early and precise diagnosis of fungal infections, and the lack of adequate and efficient drugs are responsible for the high mortality of immunocompromised patients, even in potentially curable diseases. The recognition of risk factors, introduction of prophylactic measures, application of empirical antifungal therapy, are the procedures for the reduction of morbidity and mortality of invasive fungal infections. Fluconazole administration in prevention of systemic fungal infections, has become the standard approach, especially after bone marrow transplantation, while the oral itraconazole solution, has even more extended activity. Fluconazole appears successful also in the treatment of systemic Candidiasis. Conventional amphotericin-B is still the "gold standard" in the treatment of fungal infections. The new lipid formulations of amphotericin-B, intravenous itraconazole, has an identical efficacy, but are less toxic than conventional amphotericin-B. Several new promising agents are in the stage of clinical investigation like voriconazole, caspofungin, mycafungin and some other. 相似文献
35.
2 mg/kg melanotan II (MTII, administered i.p.), a cyclic peptide analog of α-melanocyte stimulating hormone, at a single dose increased grooming in naive rats placed in an unfamiliar open-field device without changing locomotion or rearing. Male rats exposed to restraint/immobilization stress (IS) for 1 h on three consecutive days displayed increased grooming after the second stressor exposure, compared to pre-stress levels. MTII, administered to the rats after IS, enhanced the grooming response compared both to the pre- and post-stress values. The increase was greatest after the first dose and declined over the following two applications. As to the locomotion of rats in the entire experimental space, IS reduced the distance moved only after the first two stressor exposures; MTII did not influence these alterations. Locomotion in the central part of arena was not reduced by the stressor or by MTII, on the contrary, there was an increase in both groups after the third intervention. The only observed change in rearing was an increase in the MTII group after the third restraint exposure. Thus, MTII selectively increased grooming without markedly affecting the spatio-temporal structure of locomotor behavior in the open-field. The decline of MTII enhanced grooming over the three test days may be interpreted in terms of adaptation to the stressor and of the developing tolerance to the peptide. 相似文献
36.
Development of flow cytogenetics and physical genome mapping in chickpea (Cicer arietinum L.) 总被引:2,自引:0,他引:2
K. Vláčilová D. Ohri J. Vrána J. Číhalíková M. Kubaláková G. Kahl J. Doležel 《Chromosome research》2002,10(8):695-706
Procedures for flow cytometric analysis and sorting of mitotic chromosomes (flow cytogenetics) have been developed for chickpea (Cicer arietinum). Suspensions of intact chromosomes were prepared from root tips treated to achieve a high degree of metaphase synchrony. The optimal protocol consisted of a treatment of roots with 2mmol/L hydroxyurea for 18h, a 4.5-h recovery in hydroxyurea-free medium, 2h incubation with 10µmol/L oryzalin, and ice-water treatment overnight. This procedure resulted in an average metaphase index of 47%. Synchronized root tips were fixed in 2% formaldehyde for 20min, and chromosome suspensions prepared by mechanical homogenization of fixed root tips. More than 4×105 morphologically intact chromosomes could be isolated from 15 root tips. Flow cytometric analysis of DAPI-stained chromosomes resulted in histograms of relative fluorescence intensity (flow karyotypes) containing eight peaks, representing individual chromosomes and/or groups of chromosomes with a similar relative DNA content. Five peaks could be assigned to individual chromosomes (A, B, C, G, H). The purity of sorted chromosome fractions was high, and chromosomes B and H could be sorted with 100% purity. PCR on flow-sorted chromosome fractions with primers for sequence-tagged microsatellite site (STMS) markers permitted assignment of the genetic linkage group LG8 to the smallest chickpea chromosome H. This study extends the number of legume species for which flow cytogenetics is available, and demonstrates the potential of flow cytogenetics for genome mapping in chickpea. 相似文献
37.
38.
Neuropeptide Y in the female reproductive tract of the rat. Distribution of nerve fibres and motor effects 总被引:2,自引:0,他引:2
The spontaneous firing of single neurones in the region of the lateral reticular nucleus was the subject of a pharmacological study employing microiontophoretic and systemic application of adrenoceptor agonists and antagonists. Both iontophoretic noradrenaline and systemic clonidine depressed neuronal firing. The depressions were consistently reversed by the alpha-2 antagonist RX781094. Other adrenergic antagonists, prazosin and sotalol, were ineffective. The results suggest the existence of alpha-2 receptors in this region of the brain. 相似文献
39.
L. Janský P. Šrámek J. Šavlíková B. Uličný H. Janáková K. Horký 《European journal of applied physiology》1996,74(1-2):148-152
The purpose of this study was to determine whether or not repeated short-term cold water immersions can induce a change in the activity of the sympathetic nervous system and, consequently, in cardiovascular functions in healthy young athletes. Changes in some plasma hormone concentrations were also followed. A single cold water immersion (head-out, at 14°C, for 1 h) increased sympathetic nervous system activity, as evidenced by a four-fold increase (P < 0.05) in plasma noradrenaline concentration. Plasma adrenaline and dopamine concentrations were not increased significantly. Plasma renin-angiotensin activity was reduced by half (P < 0.05) during immersion but plasma aldosterone concentration was unchanged. Stimulation of the sympathetic nervous system during immersion did not induce significant changes in heart rate, but induced peripheral vasoconstriction (as judged from a decrease in skin temperature) and a small increase (by 10%) in systolic and diastolic blood pressures. No clear change in reactivity of the sympathetic nervous system was observed due to repeated cold water immersions (three times a week, for 6 weeks). Neither the plasma renin-angiotensin activity, aldosterone concentration nor cardiovascular parameters were significantly influenced by repeated cold water immersions. A lowered diastolic pressure and an increase in peripheral vasoconstriction were observed after cold acclimation, however. Evidently, the repeated cold stimuli were not sufficient to induce significant adaptational changes in sympathetic activity and hormone production. 相似文献
40.
Ioana Maris Sabine Dölle-Bierke Jean-Marie Renaudin Lars Lange Alice Koehli Thomas Spindler Jonathan Hourihane Kathrin Scherer Katja Nemat C. Kemen Irena Neustädter Christian Vogelberg Thomas Reese Ismail Yildiz Zsolt Szepfalusi Hagen Ott Helen Straube Nikolaos G. Papadopoulos Susanne Hämmerling Ute Staden Michael Polz Tihomir Mustakov Ewa Cichocka-Jarosz Renata Cocco Alessandro Giovanni Fiocchi Montserrat Fernandez-Rivas Margitta Worm Network for Online Registration of Anaphylaxis 《Allergy》2021,76(5):1517-1527