全文获取类型
收费全文 | 8110篇 |
免费 | 671篇 |
国内免费 | 227篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 1114篇 |
妇产科学 | 154篇 |
基础医学 | 640篇 |
口腔科学 | 130篇 |
临床医学 | 432篇 |
内科学 | 609篇 |
皮肤病学 | 58篇 |
神经病学 | 63篇 |
特种医学 | 108篇 |
外国民族医学 | 1篇 |
外科学 | 249篇 |
综合类 | 1042篇 |
预防医学 | 1219篇 |
眼科学 | 5篇 |
药学 | 1647篇 |
10篇 | |
中国医学 | 1447篇 |
肿瘤学 | 70篇 |
出版年
2024年 | 18篇 |
2023年 | 90篇 |
2022年 | 216篇 |
2021年 | 614篇 |
2020年 | 329篇 |
2019年 | 273篇 |
2018年 | 284篇 |
2017年 | 318篇 |
2016年 | 333篇 |
2015年 | 326篇 |
2014年 | 627篇 |
2013年 | 675篇 |
2012年 | 465篇 |
2011年 | 506篇 |
2010年 | 373篇 |
2009年 | 323篇 |
2008年 | 296篇 |
2007年 | 300篇 |
2006年 | 262篇 |
2005年 | 235篇 |
2004年 | 217篇 |
2003年 | 184篇 |
2002年 | 177篇 |
2001年 | 148篇 |
2000年 | 128篇 |
1999年 | 107篇 |
1998年 | 99篇 |
1997年 | 92篇 |
1996年 | 93篇 |
1995年 | 75篇 |
1994年 | 101篇 |
1993年 | 67篇 |
1992年 | 63篇 |
1991年 | 43篇 |
1990年 | 42篇 |
1989年 | 45篇 |
1988年 | 48篇 |
1987年 | 43篇 |
1986年 | 51篇 |
1985年 | 38篇 |
1984年 | 45篇 |
1983年 | 43篇 |
1982年 | 61篇 |
1981年 | 34篇 |
1980年 | 21篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 8篇 |
1975年 | 8篇 |
排序方式: 共有9008条查询结果,搜索用时 250 毫秒
71.
M. El‐Batawy A. S. Zahran S. A. Madkor C. J. Smith 《Food and Agricultural Immunology》1993,5(1):57-60
An enzyme‐linked immunosorbent assay (ELISA) for the detection of porcine pepsin in milk‐clotting enzyme preparations has been developed. The assay is capable of detecting porcine pepsin in the range 1 μgto 1 mg ml‐1 without enhancement or modification. The specificity of the technique was studied by inhibition assay. Slight cross‐reactions with bovine rennet and Mucor miehei rennet occurred at high concentrations (1.0 mg ml‐1). The ELISA used in this investigation appears to provide a quick, sensitive and specific method for the detection of porcine pepsin and has potential applications in the dairy industry. 相似文献
72.
Identification of casein as the major allergenic and antigenic protein of cow's milk 总被引:2,自引:3,他引:2
The objective of this study was to analyze both the allergenicity and immunogenicity of cow's milk proteins. To this end, 80 milk-atopic patients were selected on the basis of the presence of cow's milk-specific IgE antibodies in serum and compatible clinical history. Fifteen patients allergic to other allergens and 10 nonatopic subjects were studied as controls. The specificity of serum IgG and IgE antibodies was determined by immunoblotting, employing both cow's milk and milk components, i.e., α- and β-casein, β-lactoglobulin, and α-lactalbumin separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The experiments showed that casein-specific IgE antibodies were present in all (80/80) sera examined; 10/80 showed reactivity to α-lactoglobulin, and 5/80 showed reactivity to α-lactalbumin. None of the 25 negative control sera analyzed showed the presence of specific IgE antibodies against milk proteins. These results were similar to those corresponding to the detection, by the radioallergosorbent test, of IgE antibodies against the milk components coupled to paper disks. All sera from milk-atopic patients also showed IgE reactivity against a high-molecular-mass fraction that hardly enters the gel. This fraction, after separation by gel filtration and treatment with β-mercaptoethanol and urea, was shown by SDS-PAGE analysis to be formed by casein monomers. All sera analyzed by immunoblotting reacted against the components corresponding to casein monomers. Inhibition of immunoblotting by adsorption with different milk components confirmed that those high-molecular-mass aggregates are formed by casein components. The results presented here strongly suggest that casein is the major allergenic component of cow's milk. 相似文献
73.
Barbara Bellioni-Businco MDa Roberto Paganelli MDa Patrizia Lucenti MDb Paolo G. Giampietro MDb Hans Perbornc Luisa Businco MDb 《The Journal of allergy and clinical immunology》1999,103(6):1191-1194
BACKGROUND: Cow's milk allergy (CMA) is a common disease of infancy and childhood. An appropriate cow's milk (CM) substitute is necessary for feeding babies with CMA. CM substitutes are soy formulas and casein- or whey-based extensively hydrolyzed formulas. In several countries, including Italy, goat's milk (GM) formulas are available, and some physicians recommend them for feeding babies with CMA. OBJECTIVE: We sought to investigate, in vitro and in vivo, the allergenicity of GM in 26 children with proven IgE-mediated CMA. METHODS: All the children underwent skin tests with CM and GM; detection of specific serum IgE to CM and GM; and double-blind, placebo-controlled, oral food challenges (DBPCOFCs) with fresh CM, GM, and, as placebo, a soy formula (Isomil, Abbott, Italy). CAP inhibition and immunoblotting inhibition assays were also carried out in 1 of 26 and 4 of 26 children with positive RAST results to both CM and GM, respectively. RESULTS: All the children had positive skin test responses and CAP results to both CM and GM, all had positive DBPCOFC results to CM, and 24 of 26 had positive DBPCOFCs to GM. In CAP inhibition tests, preincubation of serum with CM or GM strongly inhibited IgE either to CM or to GM. In immunoblotting inhibition assays, preincubation with CM completely extinguished reactivity to GM, whereas GM partially inhibited reactivity to CM. CONCLUSIONS: These data strongly indicate that GM is not an appropriate CM substitute for children with IgE-mediated CMA. A warning on the lack of safety of GM for children with CMA should be on the label of GM formulas to prevent severe allergic reactions in babies with CMA. 相似文献
74.
Osamu Kawamura Dian‐Sheng Wang Yi‐Xin Liang Akihiro Hasegawa Chika Saga Angelo Visconti 《Food and Agricultural Immunology》1994,6(4):465-467
A survey of AFM1 residues in 58 commercial milk powder samples was carried out using an enzyme‐linked immunosorbent assay (ELISA) based on a monoclonal antibody against aflatoxin M1 (AFM1). The samples were collected from the USA (10), China (28), Italy (14), New Zealand (3) and Poland (3). The ELISA was performed without the need for clean‐up procedures. The data revealed that 4 (US), 21 (Chinese) and 1 (Polish) samples were positive for AFM1, with an average of 95.5, 102.8 and 85.0 pg g‐1 of the AFM1respectively. 相似文献
75.
76.
C. Castro R. Martín T. García E. Rodríguez I. González B. Sanz 《Food and Agricultural Immunology》1992,4(1):11-18
An indirect enzyme‐linked immunosorbent assay (ELISA) has been developed for the specific detection of cow's milk (1–25%) in goat's milk. The test uses polyclonal antibodies raised in rabbits against bovine whey proteins (BWP). The anti‐BWP antibodies were recovered from the crude antiserum by immunoadsorption and elution from a column containing immobilized BWP. The anti‐BWP antibodies were biotinylated and rendered cow's milk specific by mixing them with lyophilized ovine and caprine whey proteins. Streptavidin‐peroxidase was used to detect the biotinylated anti‐BWP antibodies bound to bovine milk proteins immobilized on 96‐well plates. The colour developed by the subsequent enzymic conversion of the substrate gave clear absorbance differences when assaying mixtures of goat's milk containing variable amounts of cow's milk. 相似文献
77.
目的:研究注射用清开灵冻干粉对临床分离致病菌的体外抗菌活性。方法:注射用清开灵冻干粉与市售清开灵注射液作比较,采用二倍稀释法,测定注射用清开灵冻干粉浓缩液对临床分离的47株致病菌的最低抑菌浓度(MIC)及最低杀菌浓度(憾),观察注射用清开灵冻干粉体外抗菌活性。结果:对金葡菌、大肠埃希菌、铜绿假单孢菌、肺炎克雷伯菌,注射用清开灵冻干粉与市售清开灵注射液均显示出良好的体外抗菌活性,注射用清开灵冻干粉体外抗菌活性强于市售清开灵注射液。按药液稀释度计算,注射用清开灵冻干粉浓缩液对金葡菌、大肠埃希菌、铜绿假单孢菌、肺炎克雷伯菌的MIC和MBC分别为市售清开灵注射液的1/4-1/2。结论:注射用清开灵冻干粉对临床分离的致病菌,具有较好的抗菌活性,且略优于市售清开灵注射液。 相似文献
78.
Four types of proteolytic activity were detected in the bloodstream form of each of the four Trypanosoma species: (i) HPAase, active on hide powder azure and detected on polyacrylamide gels containing denatured haemoglobin; (ii) AZCase, active on azocasein; (iii) type 1, active on the chromogenic peptide N-benzoyl-L-prolyl-L-phenylalanyl-L-arginine p-nitroanilide in the presence of dithiothreitol, and (iv) type 2, active against several nitroanilide derivatives in the absence of dithiothreitol. Studies of the pH optimum, dithiothreitol requirement and inhibitor sensitivities of the proteolytic activities suggested that: (a) HPAase and type 1 activities could be due to the same enzymes, probably a family of cysteine proteinases; (b) AZCase had some characteristics of a cysteine proteinase, but was not identical to HPAase, and (c) type 2 activity could be due to a serine proteinase. Procyclic T. brucei contained relatively low cysteine proteinase activities (HPAase, AZCase and type 1) but high type 2 activity. Their proteolytic enzymes thus were apparently more similar to those in Crithidia fasciculata and Leishmania tarentolae promastigotes than those in T. brucei bloodstream forms. 相似文献
79.
Formoterol administered by a dry-powder (DP) capsule inhaler was compared with a pressurized metered-dose inhaler (pMDI) with regard to bronchodilating and systemic effects. The study used a double-blind, crossover, double-dummy technique. Twelve patients with moderate reversible asthma in a stable phase were examined on two separate study days, and the inhalers were given in randomized order. After baseline measurements, increasing doses of formoterol were given at intervals of 75 min. FEV1 and heart rate and tremor measurements were repeated after each dose, and the doses were 12 + 12 + 24 + 48 μg, giving a total dose of 96 μg. The peak expiratory flow rate (PEFR) was recorded in the morning before the first dose, after the last dose, and then repeatedly at home until 19 h after the last dose. There was an equal increase in ventilatory capacity at each dose level, independent of inhaler device. Repeated PEFR measurements after the last dose did not reveal any differences in duration of effect. There was a slight but statistically significant increase in heart rate and tremor after the highest doses of the DP formulation compared to the pMDI. These systemic effects can probably be explained by the reduced oral deposition of the aerosol caused by using a spacer. This study indicates that the DP and pMDI formulations of formoterol are equipotent in bronchodilation. 相似文献
80.
U. Schulmeister I. Swoboda S. Quirce B. de la Hoz M. Ollert G. Pauli R. Valenta S. Spitzauer 《Clinical and experimental allergy》2008,38(1):60-68
Background Allergy to milk is one of the earliest manifestations of IgE‐mediated allergies and affects about 2.5% of newborn children. Several reports indicate that milk‐allergic patients may be sensitized also to human milk proteins. Objective To analyse the specificity and possible biological relevance of IgE reactivity to human milk antigens in milk‐allergic patients. Methods The specificity of IgE reactivity to cow's milk and human milk antigens was analysed with sera from milk‐allergic children and adults by IgE immunoblotting. IgE cross‐reactivity between milk antigens was studied by immunoblot inhibition experiments. That IgE reactivity to human milk antigens is not due to alloreactivity or due to the transmission of foreign antigens into mother's milk was demonstrated through the analysis of milk samples from genetically unrelated mothers before and after intake of dietary milk products. The biological relevance of IgE reactivity to human milk was confirmed by skin testing. Results IgE antibodies to human milk were found in more than 80% of the tested milk‐allergic patients. Cross‐reactive IgE‐reactive human antigens such as α‐lactalbumin and non‐cross‐reactive human milk antigens were identified. Immediate‐type skin reactions could be elicited with human milk samples in patients with IgE reactivity to human milk. Conclusion IgE reactivity to human milk in milk‐allergic patients can be due to cross‐ sensitization and genuine sensitization to human milk and may cause allergic symptoms. IgE‐mediated sensitization to human milk is common in milk‐allergic patients and may require diagnostic testing and monitoring. 相似文献