全文获取类型
收费全文 | 9040篇 |
免费 | 792篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 72篇 |
儿科学 | 339篇 |
妇产科学 | 285篇 |
基础医学 | 1100篇 |
口腔科学 | 407篇 |
临床医学 | 799篇 |
内科学 | 1759篇 |
皮肤病学 | 119篇 |
神经病学 | 1025篇 |
特种医学 | 617篇 |
外科学 | 1166篇 |
综合类 | 150篇 |
一般理论 | 9篇 |
预防医学 | 907篇 |
眼科学 | 165篇 |
药学 | 574篇 |
中国医学 | 6篇 |
肿瘤学 | 387篇 |
出版年
2022年 | 75篇 |
2021年 | 156篇 |
2020年 | 115篇 |
2019年 | 137篇 |
2018年 | 138篇 |
2017年 | 122篇 |
2016年 | 131篇 |
2015年 | 145篇 |
2014年 | 219篇 |
2013年 | 309篇 |
2012年 | 365篇 |
2011年 | 398篇 |
2010年 | 237篇 |
2009年 | 294篇 |
2008年 | 387篇 |
2007年 | 442篇 |
2006年 | 386篇 |
2005年 | 406篇 |
2004年 | 368篇 |
2003年 | 357篇 |
2002年 | 332篇 |
2001年 | 276篇 |
2000年 | 287篇 |
1999年 | 282篇 |
1998年 | 132篇 |
1997年 | 126篇 |
1996年 | 141篇 |
1995年 | 129篇 |
1994年 | 98篇 |
1993年 | 119篇 |
1992年 | 198篇 |
1991年 | 176篇 |
1990年 | 169篇 |
1989年 | 132篇 |
1988年 | 146篇 |
1987年 | 152篇 |
1986年 | 176篇 |
1985年 | 145篇 |
1984年 | 130篇 |
1983年 | 98篇 |
1982年 | 87篇 |
1980年 | 64篇 |
1979年 | 95篇 |
1978年 | 70篇 |
1977年 | 58篇 |
1975年 | 71篇 |
1974年 | 70篇 |
1973年 | 58篇 |
1972年 | 60篇 |
1969年 | 59篇 |
排序方式: 共有9886条查询结果,搜索用时 15 毫秒
61.
62.
Airway eosinophilia and expression of interleukin-5 protein in asthma and in exacerbations of chronic bronchitis 总被引:6,自引:0,他引:6
M. SAETTA A. DI STEFANO P. MAESTRELLI G. TURATO CE. MAPP M. PIENO G. ZANGUOCHI G. DEL PRETE† L. M. FABBRI 《Clinical and experimental allergy》1996,26(7):766-774
Background An increased nutnber of eosinophils in the bronchial mucosa has been demonstrated both in asthma and in exacerbations of chronic bronchitis. Oiyective To investigate whether the airway eosinophilia present in asthma and in chronic bronchitis during exacerbations is associated with interleukin (IL)-5 protein expression in the bronchial mucosa. Methods We obtained bronchial biopsies in 18 subjects with asthma (four intrinsic, seven extrinsic and seven occupational) and in II subjects with chronic bronchitis examined during an exacerbation. The findings were compared wilh those of bronchial biopsies from 10 subjects with chronic bronchitis examined under baseline conditions and from seven normal subjects, taken as controls. By immunohistochemistry, we assessed the expression of IL-5 protein and the number of eosinophils (EG2), mast cells ftryptase), and T-lymphocytes (CD3) in the submucosa. Results As compared with controls, the number of eosinophils was increased to a similar degree in both asthma (P < 0.001) and in exacerbations of ehronic bronchitis (P < 0.001). whereas the number of I L-5 immunopositive cells was increased significantly only in asthma (P < 0.01). No diflerences were observed in the number of tnast cells and T-lymphocytes between the four groups of subjects examined. Conciusions This study shows that the degree of airway eosinophilia is similar in asthma and in exacerbations of ehronic bronchitis, but only in asthma is it associated with an increased expression of I L-5 protein in the bronchial tnucosa. 相似文献
63.
A Berlin R A Bhopal J Spencer T Van Zwanenberg 《The British journal of general practice》1993,43(367):70-72
General practitioners complete approximately 26% of death certificates themselves but have considerable difficulty obtaining prompt and accurate information about their other patients who die. A random survey of district health authorities in England revealed that all were able to compile death lists but none included general practitioner details. This paper reviews the flow of information on patient deaths and describes a project to assess the feasibility of providing Newcastle general practitioners with comprehensive death registers. With the collaboration of the family health services authority and the district health authority, and with data from the regional perinatal mortality survey the creation each week of complete lists of patient deaths, broken down by general practitioner, is feasible. Death registers allow general practitioners to undertake audit of the quality of death certification and of the care of the recently deceased, and to improve the continuing care of the bereaved. 相似文献
64.
Anete M. Francisco‐Bagnariolli Spencer L.M. Payão Rosa S. Kawasaki‐Oyama Daher Sabbag Filho Rosimeire Segato Roger W. de Labio Maria de Lourdes L.F. Chauffaille Jean H. Priest 《American journal of medical genetics. Part A》2001,103(4):302-307
We report on a familial t(4;7)(q28;p22) with 2:2 adjacent‐1 unbalanced segregation producing duplication of 4q28→qter in multiple offspring. Within the large four‐generation pedigree, a carrier had a reproductive outcome that was approximately equal for 1) the balanced translocation, 2) normal chromosomes, and 3) viable 4q trisomy or pregnancy loss. The three individuals with chromosomal confirmation of trisomy 4q28→qter (comprising approximately 1.8% of the haploid autosomal length) had similar mental and developmental retardation, hypotonia, restricted speech, seizures, and facial anomalies but no cardiac, renal, or skeletal anomalies. It is suggested that these latter severe malformations, associated with the classic 4q2 to 3 group of anomalies, were from an imbalance outside 4q28→qter and were not necessarily related to the relatively large size of the trisomic segment. Multiple different chromosomes are reported to be rearranged with 4q in the production of distal 4q trisomy. The incidence of 4q rearrangement remains unexplained, but once it is present in a family, viability of a large trisomy in 4q seems to explain the number of affected individuals reported. © 2001 Wiley‐Liss, Inc. 相似文献
65.
Katz JL Spencer P Nomura T Wagh A Wang Y 《Journal of biomedical materials research. Part A》2003,66(1):120-128
In a previous study, we reported the upper limit of Young's modulus of the unprotected protein at the dentin/adhesive interface to be 2 GPa. In this study, to obtain a more exact value of the moduli of the components at the d/a interface, we used demineralized dentin collagen with and without adhesive infiltration. The prepared samples were analyzed using micro-Raman spectroscopy (micro RS) and scanning acoustic microscopy (SAM). Using an Olympus UH3 SAM (Olympus Co., Tokyo), measurements were recorded with a 400 MHz burst mode lens (120 degrees aperture angle; nominal lateral resolution, 2.5 microm). A series of calibration curves were prepared using the relationship between the ultrasonically measured elastic moduli of a set of known materials and their SAM response. Finally, both the bulk and bar wave elastic moduli were computed for a set of 13 materials, including polymers, ceramics, and metals. These provided the rationale for using extensional wave measurements of the elastic moduli as the basis for extrapolation of the 400 MHz SAM data to obtain Young's moduli for the samples: E = 1.76 +/- 0.00 GPa for the collagen alone; E = 1.84 +/- 0.65 GPa for the collagen infiltrated with adhesive; E = 3.4 +/- 1.00 GPa for the adhesive infiltrate. 相似文献
66.
Neutrophil activity in abscess-bearing mice: comparative studies with neutrophils isolated from peripheral blood, elicited peritoneal exudates, and abscesses. 总被引:1,自引:5,他引:1 下载免费PDF全文
P H Hart L K Spencer M F Nulsen P J McDonald J J Finlay-Jones 《Infection and immunity》1986,51(3):936-941
Intraabdominal abscesses were induced in mice by intraperitoneal inoculation of Bacteroides fragilis and Escherichia coli plus bran as the abscess-potentiating agent. Six- or seven-day-old abscesses were mechanically disaggregated in buffer, and the cells obtained were fractionated on discontinuous Percoll density gradients. Neutrophil populations of different density, each approximately 90% pure, were isolated. When the abscess-derived neutrophils were subsequently incubated with normal serum in vitro under aerobic conditions, the viability of the gram-negative bacteria that had been phagocytosed within the abscess did not change significantly. This anergy to intracellular bacteria (on subsequent incubation in vitro under optimal conditions for phagocytic killing) was also found for neutrophils that had been obtained from abscesses induced by a mixture that included Proteus mirabilis plus B. fragilis and from those induced by E. coli plus P. mirabilis. While unable to significantly kill intracellular organisms that had been phagocytosed in vivo, the abscess-derived neutrophils could engulf and kill organisms to which they were exposed in vitro. Neutrophils from abscesses induced by P. mirabilis only plus bran killed that organism introduced in vitro significantly more effectively than the organisms that had been engulfed in vivo. In contrast, neutrophils from abscesses induced by the gram-positive organism Staphylococcus aureus plus bran were able to kill their intracellular organisms on subsequent incubation in vitro as effectively as they could kill added S. aureus. Neutrophils isolated from the peripheral blood and from induced peritoneal exudates of abscess-bearing mice were able to phagocytose and kill organisms in vitro with greater efficiency than abscess-derived neutrophils. The mechanism whereby neutrophils from abscesses induced by the gram-positive organism S. aureus can kill the organisms phagocytosed in vivo on subsequent in vitro incubation, in contrast to the relative anergy to their intracellular organisms displayed by neutrophils derived from abscesses induced by combinations of gram-negative bacteria, is not known. 相似文献
67.
Jacques R. Caldwell David E. Pearce Craig Spencer Rosmarie Leder Robert H. Waldman 《The Journal of allergy and clinical immunology》1973,52(4):225-230
Immunologic studies were performed on 5 patients with pigeon breeders' disease. Intradermal injection of pigeon serum produced an immediate wheal-and-flare reaction within 15 minutes and a secondary Arthus-type reaction within 4 to 8 hours. Immunofluorescent studies of the secondary reaction site showed IgG, C3, and C4 in 2 patients. Patients' sera produced multiple precipitin bands with pigeon serum when reacted by double diffusion in gel. IgG antibody isolated from each of the patients' serum formed precipitating immune complexes that fixed large amounts of complement (C4) when added to fresh human serum. Peripheral blood lymphocytes from 4 of the 5 patients produced macrophage migration inhibitory factor (MIF) when challenged with dilute pigeon serum. These studies are the first to show complement fixing antibodies and macrophage MIF production by lymphocytes from patients with hypersensitivity lung disease and suggest that both humoral and cellular immunity may be important in the pathogenesis of these disorders. 相似文献
68.
Development of neural processes underlying integration of phonological and orthographic information were assessed by measuring event-related brain potentials (ERPs), judgment accuracies and reaction times (RTs) in 20 children (9-10 years) and 20 adults performing visual rhyme judgments. Half the trials were phonologically and orthographically congruent across the prime-target pairs (e.g., thrown-own, cake-own), and half were incongruent (e.g., gown-own, cone-own). For both children and adults, behavioral performance was most affected when different phonological representations had to be encoded from similar orthographic representations (e.g., gown-own), and the amplitudes of the N350 reflected effects of both rhyme and phonological/orthographic congruency. Latencies of the N350 were shorter over the left hemisphere only in adults, and phonological/orthographic incongruence produced greater delays in children's processing. Therefore, it appears that neural systems mediating rhyming judgments develop early; however, adults exhibit increased efficiency for left-hemisphere processing and are less affected by interference from incongruent phonological and orthographic codes. 相似文献
69.
Audit and academic departments of general practice: a survey in the United Kingdom and Eire. 下载免费PDF全文
J A Spencer 《The British journal of general practice》1992,42(361):333-335
A questionnaire and telephone survey was carried out in April 1991 of all 31 academic departments of general practice in the United Kingdom and Eire; 30 departments responded. The aim of the study was to assess the departments' level of involvement in teaching about audit in the undergraduate curriculum, their role in the development of audit in primary care including involvement with medical audit advisory groups, whether they undertook teaching about audit to other health professionals and whether they were involved in audit related research. Eleven of 27 responding undergraduate departments provided formal teaching about audit and five intended to introduce it in the near future. Respondents expressed concerns about teaching audit to undergraduates, including lack of time in the curriculum, difficulties making the teaching relevant and interesting, and a lack of expertise and knowledge of the subject among the staff. All 29 departments in the UK were represented on medical audit advisory groups, and audit related research was being carried out in 24 undergraduate departments. The role of academic departments of general practice in the development of audit in primary care is discussed. 相似文献
70.