全文获取类型
收费全文 | 2723篇 |
免费 | 173篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 77篇 |
妇产科学 | 126篇 |
基础医学 | 401篇 |
口腔科学 | 69篇 |
临床医学 | 225篇 |
内科学 | 419篇 |
皮肤病学 | 60篇 |
神经病学 | 300篇 |
特种医学 | 81篇 |
外科学 | 312篇 |
综合类 | 18篇 |
预防医学 | 159篇 |
眼科学 | 61篇 |
药学 | 192篇 |
中国医学 | 7篇 |
肿瘤学 | 374篇 |
出版年
2023年 | 12篇 |
2022年 | 30篇 |
2021年 | 64篇 |
2020年 | 30篇 |
2019年 | 55篇 |
2018年 | 62篇 |
2017年 | 48篇 |
2016年 | 57篇 |
2015年 | 50篇 |
2014年 | 69篇 |
2013年 | 119篇 |
2012年 | 148篇 |
2011年 | 185篇 |
2010年 | 95篇 |
2009年 | 107篇 |
2008年 | 135篇 |
2007年 | 175篇 |
2006年 | 132篇 |
2005年 | 150篇 |
2004年 | 132篇 |
2003年 | 130篇 |
2002年 | 132篇 |
2001年 | 88篇 |
2000年 | 86篇 |
1999年 | 72篇 |
1998年 | 46篇 |
1997年 | 36篇 |
1996年 | 29篇 |
1995年 | 31篇 |
1994年 | 22篇 |
1993年 | 19篇 |
1992年 | 47篇 |
1991年 | 47篇 |
1990年 | 27篇 |
1989年 | 21篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1976年 | 7篇 |
1971年 | 7篇 |
1970年 | 5篇 |
1968年 | 5篇 |
排序方式: 共有2906条查询结果,搜索用时 15 毫秒
91.
Zee RY Solomon SD Ajani UA Pfeffer MA Lindpaintner K;Heart investigators 《Clinical genetics》2002,61(1):21-25
The D/I (deletion, D, insertion, I) polymorphism of the angiotensin-converting enzyme (ACE) gene has been extensively studied for its association with a number of cardiovascular and other disease states. However, its potential association with differential clinical efficacy of ACE inhibitors (ACE-I) administered to patients who had suffered a myocardial infarction (MI), i.e. the prevention of left ventricular (LV) remodeling, has so far not been specifically studied. The aim of the study was to investigate whether the D/I polymorphism of the ACE gene is associated with the incidence of post-MI LV remodeling in patients drawn from the 'Healing and Early Afterload Reducing Therapy' (HEART) Study. The ACE D/I polymorphism was characterized by the polymerase chain reaction (PCR) in 265 subjects from the 'Healing and Early Afterload Reducing Therapy' Study, a double-blind, placebo-controlled trial with the objective of determining whether early or delayed administration of the ACE-I, ramipril, in patients with acute anterior wall MI would be optimal in reducing LV enlargement. Selected frequencies for the ACE D and I alleles were 0.59 and 0.41 (placebo-high dose group), 0.56 and 0.44 (low dose-low dose group), and, 0.60 and 0.40 (high dose-high dose group), respectively. All observed genotype frequencies were in Hardy-Weinberg equilibrium. There was no evidence for an association between genotype and outcome regarding LV size or function, nor with the initial blood pressure response after ACE-I administration (adjusted for covariates). Our data provide no evidence for an association of the ACE D/I polymorphism with the risk of LV remodeling post-MI in the presence of ACE-I therapy, and therefore do not suggest that differential clinical efficacy of ACE-inhibitors is related to this genetic marker. 相似文献
92.
Fang X Yu MM Yuen WH Zee SY Chang RC 《International journal of molecular medicine》2005,16(6):1109-1116
Prunella vulgaris L. (Labiatae), a popular Western and Chinese herbal medicine, has long been associated with anti-viral and anti-bacterial effects. While its anti-viral effects are attributed mainly to the inhibition of virus replication, the biological mechanisms of its anti-bacterial effects remain unknown. As a biological response modifier (BRM), the polysaccharides isolated from P. vulgaris have been shown to up-regulate the immune responses of monocytes/macrophages. However, the immune stimulatory effects seem to contradict its well-known anti-inflammatory properties. We hypothesized that the anti-microbial effects exhibited by the polysaccharides isolated from P. vulgaris encompass both anti-inflammatory and immune stimulatory effects. One of the polysaccharide fractions PV2IV markedly stimulated the production of superoxide and nitrite representing nitric oxide from murine macrophage RAW264.7 and brain macrophage BV2 cells. The amount of nitrite and superoxide produced after PV2IV stimulation was as high as that stimulated by bacterial endotoxin lipopolysaccharide (LPS) in a dose-dependent manner. In addition, PV2IV also increased cellular protein levels of inducible nitric oxide synthase (iNOS) and mRNA for tumor necrosis factor-alpha (TNFalpha). Similar to the effects of a high dose of LPS, the fraction PV2 could trigger activation-induced cell death (AICD) by stimulating caspase-3 activity and reduction of MTT uptake in monocytes/macrophages. These results may help our understanding of the molecular mechanism of P. vulgaris, which exhibited both immune stimulatory and anti-inflammatory effects against microbial invasion. 相似文献
93.
Adding salmeterol to an inhaled corticosteroid reduces allergen-induced serum IL-5 and peripheral blood eosinophils 总被引:3,自引:0,他引:3
Koopmans JG Lutter R Jansen HM van der Zee JS 《The Journal of allergy and clinical immunology》2005,116(5):1007-1013
BACKGROUND: Adding a long-acting beta(2)-agonist to inhaled corticosteroids results in better symptomatic asthma control than increasing the dose of inhaled corticosteroids. OBJECTIVE: Investigating whether adding the long-acting beta(2)-agonist salmeterol to the inhaled corticosteroid fluticasone propionate has an effect on allergen-induced allergic inflammation in asthma. METHODS: Bronchial allergen challenges were performed in 26 patients with allergic asthma, pretreating them with a single dose of either fluticasone/salmeterol (100/50 microg) or fluticasone alone (100 microg), in a double-blind, randomized, cross-over design. Sputum and serum markers of bronchial inflammation were measured after allergen challenge, as well as lung function parameters. Primary outcomes were sputum eosinophil numbers and eosinophil cationic protein. RESULTS: Asthmatic responses after allergen challenge were significantly reduced after pretreatment with fluticasone/salmeterol relative to fluticasone alone. Sputum inflammatory markers after allergen challenge were not significantly affected by fluticasone/salmeterol pretreatment. By contrast, serum IL-5 was significantly reduced (geometric mean serum IL-5 [SEM]: 0.5 [0.3] vs 1.1 [0.3] pg/mL 1 hour and 0.6 [0.3] vs 1.1 [0.3] pg/mL 6 hours after challenge with fluticasone/salmeterol vs fluticasone alone pretreatment, respectively; P values < .05). Also, peripheral blood eosinophils were significantly reduced (geometric mean number x 10(6)/L [SEM]: 172 [0.1] vs 237 [0.1] at 6 hours and 271 [0.1] vs 351 [0.1] at 24 hours with fluticasone/salmeterol vs fluticasone alone pretreatment, respectively; P < .05). CONCLUSION: Adding salmeterol to fluticasone reduces allergen-induced serum IL-5 and peripheral blood eosinophils. This phenomenon may contribute to the improved clinical outcomes that result from adding a long-acting beta(2)-agonist to inhaled corticosteroids. 相似文献
94.
Aktas M de Jong D Nuyttens JJ van der Zee J Wielheesen DH Batman E Burger CW Ansink AC 《European journal of obstetrics, gynecology, and reproductive biology》2007,133(1):100-104
OBJECTIVE: To evaluate the supplementary value of adding hyperthermia to radiotherapy in patients with primary vaginal cancer. STUDY DESIGN: Cohort of 44 patients diagnosed with primary vaginal cancer between 1990 and 2002 was assessed. Survival rates and median survival of patients with primary vaginal cancer undergoing radiotherapy with and without hyperthermia were compared. Hyperthermia was solely added to radiotherapy in case of a tumor size >4 cm in diameter for FIGO stage III disease. RESULTS: The calculated overall 5-year survival of primary vaginal cancer was 63%. In comparison to histologic high grade tumors, higher survival rates for histologic low grade tumors were calculated. For FIGO stage III of disease, the addition of hyperthermia to radiotherapy for tumors >4 cm in diameter resulted similar survival rates and median survival when compared to those achieved by radiotherapy as monotherapy in tumors of <4 cm in diameter. CONCLUSIONS: The addition of hyperthermia to radiotherapy might result in better survival rates in primary vaginal cancer for tumors >4 cm in diameter. The supplementary effect of hyperthermia to radiotherapy may be a feasible and beneficial approach in the treatment of vaginal cancer. 相似文献
95.
Service profiles of general practitioners in Europe. European GP Task Profile Study. 总被引:1,自引:0,他引:1 下载免费PDF全文
BACKGROUND: General practice is the focal point of primary care. There are national differences in the structure and organization of practice, the relationship with secondary care is being redefined, and in some countries major changes are taking place. AIM: To describe and examine differences in the service profiles of general practitioners (GPs) in European countries. METHOD: Standardized questionnaires in the national languages were sent to samples of GPs in 1993. Four areas of service provision were measured: the GP's position in the first contact with selected health problems, the involvement in minor surgery and the application of medical procedures, disease management and preventive care. The importance of the gatekeeping role, remuneration system, and geographical region in Europe was examined by comparing scores in appropriate national groupings. RESULTS: Data were received from 7233 GPs in 30 countries. Most national samples were random and the average response rate was 47%. In countries where GPs have a gatekeeping role, they had a relatively stronger position as doctors of first contact. In those countries where GPs were usually self-employed, they had a stronger role in disease management and screening for blood cholesterol. In the examination of the three structural elements of health care, the most striking differences were evident in the comparison between eastern and western Europe. GPs throughout Europe had a comparatively small role in organized health education. CONCLUSION: The position of GPs is weak in eastern Europe and some Mediterranean countries, where service profiles have a limited range. General practice was more comprehensive where the doctors had a gatekeeping role. 相似文献
96.
97.
The association between bacteria and leaves in Ardisia has been described as a cyclic and obligate symbiosis in which bacteria are maintained throughout all stages of the plant’s life cycle to guarantee normal growth and survival of the host. This intimate interaction suggests that both partners have co-diversified together. To test this co-speciation hypothesis, we constructed an endosymbiont (16S rDNA and gyrB) and host (rps16, trnL, matK and ITS) phylogeny. Phylogenetic analyses of the endosymbionts revealed a pattern of strict host specificity and recovered a single clade in the genus Burkholderia (β-proteobacteria), which was closely related to the endosymbionts of leaf-nodulated Rubiaceae. Comparison of symbiont and host phylogenies suggests a single origin of bacterial leaf symbiosis in the nodulated ancestor of Ardisia and does not reject the co-speciation hypothesis. 相似文献
98.
N.G. Alkema T. Tomar A.G.J. van der Zee M. Everts G.J. Meersma H. Hollema S. de Jong M.A.T.M. van Vugt G.B.A. Wisman 《Gynecologic oncology》2014
Objective
Platinum-based chemotherapy is the standard treatment in advanced stage high grade serous ovarian cancer (HGSOC), but the majority of patients will relapse with drug-resistant disease. Platinum induces double-strand DNA breaks and subsequently activation of the DNA damage response (DDR). Drugs targeting DDR pathway components have gained major interest to be combined with chemotherapy as they could increase the therapeutic window. In the present study, we investigated the activation status of the Ataxia Telangiectasia Mutated (ATM) signaling axis within the DDR in a large, well-defined cohort of advanced stage HGSOC patients.Methods
Pre-therapy activation status of the ATM signaling axis of the DDR was determined by immunohistochemistry in 125 chemo-naive advanced stage HGSOC patients. Ovarian cancer cell lines with stable checkpoint kinase 2 (Chk2) knock down were used to study cell cycle distribution and survival in long-term clonogenic survival assays.Results
All ATM signaling axis components showed high expression levels. In two well-defined groups with the largest contrast in treatment response, high expression of Chk2 was related to good response (OR = 0.132; P = 0.014). Chk2 depletion abrogated the cisplatin-induced S-phase cell cycle arrest and caused increased resistance to cisplatin in long-term clonogenic survival assays.Conclusions
Chk2 is related to good response to platinum-based chemotherapy in advanced stage HGSOC patients. Chk2-depleted ovarian cancer cell lines have diminished platinum sensitivity, suggesting that Chk2 should not be considered a therapeutic target along with platinum-based treatment in HGSOC patients. 相似文献99.
Aakash A. Bavishi Leslie C. Grammer Jacqueline Pongracic Karen Rychlik Rajesh Kumar Phyllis Zee Paul A. Greenberger Anna B. Fishbein 《Annals of allergy, asthma & immunology》2017,118(1):103-107
Background
Circadian rhythms underlie many immune responses and allergic diseases. Subcutaneous immunotherapy (SCIT) can result in adverse reactions; however, it is unclear whether such reactions have a diurnal pattern.Objective
To assess whether the timing of SCIT affects the rate of adverse reactions.Methods
This study was a retrospective medical record review of adult patients (n = 289) who received SCIT at the Northwestern Medical Faculty Foundation, Chicago, Illinois, during a 10-year period (2004–2014). Injections were given in the outpatient setting. There were a total of 17,457 injections with 574 reactions. Covariates included age, sex, median income, asthma status, vial contents, number of injections, and previous immunotherapy reactions. Logistical regression was used to calculate the odds of having a reaction with time of SCIT administration as the primary determinate.Results
Immunotherapy reactions occurred more frequently after afternoon or evening (pm) injections (328/8721 = 3.8%) vs morning (am) injections (246/8736 = 2.8%), (χ2 = 12.26, P < .01). Systemic reactions, defined as World Allergy Organization grade 1 or higher, did not have diurnal variation (59/8721 = 0.67% for pm vs am 56/8736 = 0.64% for morning; χ2 = 0.08; P = .77). pm injections resulted in higher odds of reaction compared with am injection in a fully adjusted logistic regression model (odds ratio = 1.43; 95% confidence interval, 1.20–1.70; P < .01). When considering time as 4 categories, the highest odds of reaction were noted for the period from 15:01 to 17:30 (odds ratio, 1.55; 95% confidence interval, 1.21–2.00; P < .01).Conclusion
pm injections of SCIT are associated with increased cutaneous reaction rates when compared with am injections. In patients experiencing bothersome local reactions, it may be beneficial to administer SCIT in the morning. 相似文献100.
Molecular Genotyping of Staphylococcus aureus Strains: Comparison of Repetitive Element Sequence-Based PCR with Various Typing Methods and Isolation of a Novel Epidemicity Marker 总被引:4,自引:0,他引:4 下载免费PDF全文
Anneke van der Zee Harold Verbakel Johan-Carlo van Zon Ine Frenay Alex van Belkum Marcel Peeters Anton Buiting Anneke Bergmans 《Journal of clinical microbiology》1999,37(2):342-349
Repetitive sequence-based (Rep)-PCR genotyping as described here is based on the presence of homologues of Mycoplasma pneumoniae repeat-like elements in Staphylococcus. In this study we comparatively evaluated the usefulness of rep-PCR typing with two sets of well-defined collections of Staphylococcus aureus strains. Rep-PCR analysis of the first collection of S. aureus strains (n = 59) and one Staphylococcus intermedius strain showed 14 different rep-PCR patterns, with each pattern harboring 6 to 15 DNA fragments. The discriminatory power of rep-PCR typing compared well to those of arbitrarily primed PCR (average of 20 types) and pulsed-field gel electrophoresis (11 types). S. aureus strain collection I comprised four outbreak-related groups of isolates. The isolates in only one group were found to have identical rep-PCR profiles. However, in an analysis of isolates from three additional independent local outbreaks (n for outbreaks 1 and 2 = 5, n for outbreak 3 = 12), identical rep-PCR types were found among strains isolated during each outbreak. Therefore, we conclude that rep-PCR genotyping may be an easy and fast method for monitoring of the epidemiology of nosocomial Staphylococcus infections. Rep-PCR analysis of strain collection II, which consisted of epidemic and nonepidemic methicillin-resistant S. aureus (MRSA) strains, revealed that a cluster of similar rep-PCR profiles was found among MRSA isolates which were more frequently isolated and which were most often associated with outbreaks. 相似文献