全文获取类型
收费全文 | 9078篇 |
免费 | 617篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 258篇 |
妇产科学 | 256篇 |
基础医学 | 1414篇 |
口腔科学 | 185篇 |
临床医学 | 1044篇 |
内科学 | 1741篇 |
皮肤病学 | 243篇 |
神经病学 | 1190篇 |
特种医学 | 236篇 |
外国民族医学 | 3篇 |
外科学 | 726篇 |
综合类 | 68篇 |
一般理论 | 9篇 |
预防医学 | 806篇 |
眼科学 | 304篇 |
药学 | 563篇 |
中国医学 | 20篇 |
肿瘤学 | 578篇 |
出版年
2023年 | 78篇 |
2022年 | 121篇 |
2021年 | 210篇 |
2020年 | 189篇 |
2019年 | 219篇 |
2018年 | 274篇 |
2017年 | 217篇 |
2016年 | 229篇 |
2015年 | 279篇 |
2014年 | 309篇 |
2013年 | 471篇 |
2012年 | 753篇 |
2011年 | 734篇 |
2010年 | 381篇 |
2009年 | 352篇 |
2008年 | 652篇 |
2007年 | 596篇 |
2006年 | 560篇 |
2005年 | 530篇 |
2004年 | 496篇 |
2003年 | 464篇 |
2002年 | 455篇 |
2001年 | 77篇 |
2000年 | 53篇 |
1999年 | 72篇 |
1998年 | 86篇 |
1997年 | 75篇 |
1996年 | 71篇 |
1995年 | 47篇 |
1994年 | 50篇 |
1993年 | 43篇 |
1992年 | 43篇 |
1991年 | 37篇 |
1990年 | 23篇 |
1989年 | 21篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 25篇 |
1985年 | 21篇 |
1984年 | 25篇 |
1983年 | 22篇 |
1982年 | 27篇 |
1980年 | 17篇 |
1979年 | 14篇 |
1978年 | 24篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1971年 | 14篇 |
1968年 | 14篇 |
排序方式: 共有9718条查询结果,搜索用时 0 毫秒
51.
Adoptive immunotherapy for posttransplantation viral infections. 总被引:1,自引:0,他引:1
Catherine M Bollard Ingrid Kuehnle Ann Leen Cliona M Rooney Helen E Heslop 《Biology of blood and marrow transplantation》2004,10(3):143-155
Viral diseases are a major cause of morbidity and mortality after hemopoietic stem cell transplantation. Because viral complications in these patients are clearly associated with the lack of recovery of virus-specific cellular immune responses, reconstitution of the host with in vitro expanded cytotoxic T lymphocytes is a potential approach to prevent and treat these diseases. Initial clinical studies of cytomegalovirus and Epstein-Barr virus in human stem cell transplant patients have shown that adoptively transferred donor-derived virus-specific T cells may restore protective immunity and control established infections. Preclinical studies are evaluating this approach for other viruses while strategies for generating T cells specific for multiple viruses to provide broader protection are being evaluated in clinical trials. The use of genetically modified T cells or the use of newer suicide genes may result in improved safety and efficacy. 相似文献
52.
Ellen R Julian Deborah J Ingersoll Patricia M Etienne Anthony E Hilger 《Academic medicine》2004,79(4):360-364
PURPOSE: Medical College Admission Test (MCAT) examinees with disabilities who receive accommodations receive flagged scores indicating nonstandard administration. This report compares MCAT examinees who received accommodations and their performances with standard examinees. METHOD: Aggregate history records of all 1994-2000 MCAT examinees were identified as flagged (2,401) or standard (297,880), then further sorted by race/ethnicity (broadly identified as underrepresented minority and non-URM, at the time of testing) and gender. Those with flagged scores were also classified by disability (LD = learning disability, ADHD = attention deficit hyperactivity disorder, LD/ADHD = learning disability and attention deficit hyperactivity disorder, and Other = other disability) and type of accommodation. Mean MCAT scores were calculated for all groups. A group of 866 examinees took the MCAT first as a standard administration and subsequently with accommodations. In a separate analysis, their two sets of scores were compared. RESULTS: Less than 1% of examinees (2,401) had accommodations; of these, 55% were LD, 17% ADHD, 5% LD/ADHD, and 23% Other. Extended time was the most frequently provided accommodation. Mean flagged scores slightly exceeded mean standard scores on all MCAT sections. Examinees who retook the MCAT with accommodations after a standard administration increased their scores by six points, quadrupling the average gain Standard-Standard retest cohort from another study. CONCLUSION: The small but statistically significant different higher flagged scores may reflect either appropriate compensation or overly generous accommodations. Extended time had a positive impact on the scores of those who retested with this accommodation. The validity the flagged MCAT in predicting success in medical school is not known, and further investigation is underway. 相似文献
53.
GABRD encoding a protein for extra- or peri-synaptic GABAA receptors is a susceptibility locus for generalized epilepsies 总被引:11,自引:0,他引:11
Dibbens LM Feng HJ Richards MC Harkin LA Hodgson BL Scott D Jenkins M Petrou S Sutherland GR Scheffer IE Berkovic SF Macdonald RL Mulley JC 《Human molecular genetics》2004,13(13):1315-1319
A major challenge in understanding complex idiopathic generalized epilepsies has been the characterization of their underlying molecular genetic basis. Here, we report that genetic variation within the GABRD gene, which encodes the GABAA receptor delta subunit, affects GABA current amplitude consistent with a model of polygenic susceptibility to epilepsy in humans. We have found a GABRD Glu177Ala variant which is heterozygously associated with generalized epilepsy with febrile seizures plus. We also report an Arg220His allele in GABRD which is present in the general population. Compared with wild-type receptors, alpha1beta2Sdelta GABAA receptors containing delta Glu177Ala or Arg220His have decreased GABAA receptor current amplitudes. As GABAA receptors mediate neuronal inhibition, the reduced receptor current associated with both variants is likely to be associated with increased neuronal excitability. Since delta subunit-containing receptors localize to extra- or peri-synaptic membranes and are thought to be involved in tonic inhibition, our results suggest that alteration of this process may contribute to the common generalized epilepsies. 相似文献
54.
Livia Maria Ionescu Ion Petrea Ingrid Ionescu Bujor Ioana Demetrescu 《Macromolecular chemistry and physics.》1983,184(5):1005-1015
Light scattering measurements from aqueous solutions for two samples of poly(acrylamide-co-maleic anhydride) in the presence of salt are conducted. One of the samples exhibits a negative initial slope and a minimum in the plot of the conventional reciprocal scattered intensity function of sin2 (θ/2). The explanation for this anomaly is a large optical anisotropy of the segment. A correction for this effect of segmental anisotropy is made. The behaviour of the other sample of this copolymer is typical for a polyelectrolyte. By analysing the disymmetry of the scattered light, the influence of the salt concentration on the polyion is evidenced by the determination of the macromolecular dimensions. Light scattering data allow the evaluation of the Mark-Kuhn-Houwink exponent a for various degrees of dissociation of the polyion; a correlation between the variation of a and the shape of the macromolecule is observed. 相似文献
55.
Taylor S Thordarson DS Maxfield L Fedoroff IC Lovell K Ogrodniczuk J 《Journal of consulting and clinical psychology》2003,71(2):330-338
The authors examined the efficacy, speed, and incidence of symptom worsening for 3 treatments of posttraumatic stress disorder (PTSD): prolonged exposure, relaxation training, or eye movement desensitization and reprocessing (EMDR; N = 60). Treaments did not differ in attrition, in the incidence of symptom worsening, or in their effects on numbing and hyperarousal symptoms. Compared with EMDR and relaxation training, exposure therapy (a) produced significantly larger reductions in avoidance and reexperiencing symptoms, (b) tended to be faster at reducing avoidance, and (c) tended to yield a greater proportion of participants who no longer met criteria for PTSD after treatment. EMDR and relaxation did not differ from one another in speed or efficacy. 相似文献
56.
We analyzed the effect of the PAF receptor antagonist (+)-cis-3,5-dimethyl-2-(3-pyridyl) thiazolidin-4-one hydrochloride (SM-12502) on the release of leukotriene B4 and IL-8 from human leukocytes. Peripheral blood from healthy donors was separated in two different fractions: polymorphonuclear leukocytes (PMN) and a lymphocyte, monocyte and basophil granulocyte cell fraction (LMB). After incubation of the cell population with different concentrations of SM-12502 the cells were subsequently stimulated with either the Ca ionophore A23187, the bacterial derived peptide fMLP, or with an activator of heterotrimetric G-proteins, the sodium fluoride (NaF, in the presence of Al3+). The PAF receptor antagonist led to a concentration and time dependent inhibition of LTB4 formation and IL-8 release from PMN and LMB. Our data clearly indicate an inhibitory effect of the PAF receptor antagonist SM-12502 on the formation of mediators of the lipoxygenase pathway and on the release of IL-8. 相似文献
57.
Markus Wahrmann Sigurd Krieger Ingrid Raab Robert Ullrich Dontscho Kerjaschki 《Molecular immunology》2007,44(16):3932-3933
58.
Clara cell protein 16 (CC16) gene polymorphism influences the degree of airway responsiveness in asthmatic children 总被引:8,自引:0,他引:8
Sengler C Heinzmann A Jerkic SP Haider A Sommerfeld C Niggemann B Lau S Forster J Schuster A Kamin W Bauer C Laing I LeSouef P Wahn U Deichmann K Nickel R 《The Journal of allergy and clinical immunology》2003,111(3):515-519
BACKGROUND: Several studies have indicated linkage of chromosome 11q12-13 to asthma and associated traits. Among other candidate genes, the Clara cell protein 16 (CC16) gene maps to this region. CC16 is expressed in the bronchial epithelium and exhibits potent anti-inflammatory properties. A single-nucleotide polymorphism (SNP) in the CC16 gene (A38G) was previously associated with asthma. OBJECTIVE: We evaluated the role of the CC16 SNP in pediatric asthma and asthma severity in 2 German study populations. METHODS: The German Multicenter Allergy Study (MAS) cohort (n = 872, 94 asthmatic patients) and 112 allergic asthmatic children recruited in Freiburg, Germany, were included in the present study. Histamine provocations were performed at the age of 7 years in the MAS cohort to determine bronchial hyperreactivity; in the Freiburg study population a standardized exercise-induced decrease in FEV1 was evaluated. For genotyping, melting-curve analysis and restriction enzyme digestion were applied. RESULTS: No association of the CC16*38A allele with asthma could be observed in either study population. However, in asthmatic subjects (MAS cohort) PC(20)FEV(1) values were significantly lower in individuals homozygous or heterozygous for the CC16*38A allele compared with those in subjects with the CC16*38GG genotype (P <.05 and P <.03, respectively). Similarly, allergic asthmatic patients in the Freiburg cohort showed a significantly greater decrease in FEV1 after exercise when homozygous for the CC16*38A allele compared with that seen in asthmatic patients with the *38AG or *38GG genotype (P <.04 and P =.006, respectively). CONCLUSION: We conclude that the CC16*A38G SNP influences bronchial hyperreactivity and might be a genetic determinant of asthma severity in German children. 相似文献
59.
Sander I Kespohl S Merget R Goldscheid N Degens PO Bruning T Raulf-Heimsoth M 《International archives of allergy and immunology》2005,136(1):39-44
BACKGROUND: Detection of allergen-specific IgE antibodies in patients' sera plays a key role for the diagnosis of IgE-mediated allergy. If no validated test system is available, diagnostic tools must be developed, usually by coupling or binding the allergens to a solid phase. Streptavidin ImmunoCAP is a new solid phase for binding of allergens which can be used in the Pharmacia CAP system. OBJECTIVE: It was the aim of this study to assess the diagnostic validity of Streptavidin ImmunoCAP. METHODS: Biotinylation and allergen concentration for binding to Streptavidin ImmunoCAP were optimized and IgE obtained with natural rubber latex, obeche wood, wheat and rye flour Streptavidin ImmunoCAP were compared with the results of ImmunoCAP and Enzyme Allergo-Sorbent Test (EAST) using sera from patients complaining of workplace-related respiratory symptoms. RESULTS: While the relation of biotin-label and protein was critical (best results were obtained with a 5- fold molar excess), labelled protein for coupling to streptavidin ImmunoCAP was applicable in a wide concentration range. On average, IgE values with streptavidin ImmunoCAP were as high as with ImmunoCAP but considerably higher than values obtained by EAST. CONCLUSION: Streptavidin ImmunoCAP is a valuable tool for sensitive and specific measurement of IgE binding to new allergens superior to cellulose disk-based methods. 相似文献
60.
Indolent systemic mastocytosis with elevated serum tryptase, absence of skin lesions, and recurrent severe anaphylactoid episodes 总被引:2,自引:0,他引:2
Florian S Krauth MT Simonitsch-Klupp I Sperr WR Fritsche-Polanz R Sonneck K Födinger M Agis H Böhm A Wimazal F Horny HP Valent P 《International archives of allergy and immunology》2005,136(3):273-280
BACKGROUND: In contrast to aggressive mastocytosis, patients with indolent systemic mastocytosis (ISM) usually present with urticaria pigmentosa-like skin lesions. In those who lack skin lesions, mastocytosis is often overlooked or confused with endocrinologic, allergic, or other internal disorders. CASE REPORT AND RESULTS: We report on a 33-year-old male patient in whom severe hypotensive episodes occurred after contact with ants or yellow jackets. Since no specific IgE was detected, the serum tryptase concentration was measured and found to be clearly elevated (70 ng/ml). Consecutive staging and examination of the bone marrow revealed ISM. The patient was advised to circumvent insect contact, to take antihistamines on demand, and to carry an epinephrine self-injector for emergency events. In a retrospective analysis of 40 patients seen between 1988 and 2003, only 2 had a life-threatening mediator-related episode before ISM was diagnosed. CONCLUSIONS: Our report confirms the diagnostic value of tryptase in patients with suspected mastocytosis. In addition, the report suggests that the lack of typical skin lesions does not exclude an indolent form of mastocytosis even if the serum tryptase is clearly elevated. Finally, our case further shows that mastocytosis can be an important differential diagnosis to be considered in patients with unexplained anaphylactoid or other mediator-related symptoms. 相似文献