全文获取类型
收费全文 | 21188篇 |
免费 | 948篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 938篇 |
儿科学 | 748篇 |
妇产科学 | 1247篇 |
基础医学 | 2588篇 |
口腔科学 | 132篇 |
临床医学 | 1447篇 |
内科学 | 4283篇 |
皮肤病学 | 266篇 |
神经病学 | 2392篇 |
特种医学 | 378篇 |
外科学 | 1565篇 |
综合类 | 78篇 |
一般理论 | 6篇 |
预防医学 | 1884篇 |
眼科学 | 592篇 |
药学 | 2723篇 |
中国医学 | 53篇 |
肿瘤学 | 858篇 |
出版年
2023年 | 115篇 |
2022年 | 140篇 |
2021年 | 288篇 |
2020年 | 220篇 |
2019年 | 363篇 |
2018年 | 681篇 |
2017年 | 463篇 |
2016年 | 522篇 |
2015年 | 449篇 |
2014年 | 757篇 |
2013年 | 1162篇 |
2012年 | 1378篇 |
2011年 | 1697篇 |
2010年 | 890篇 |
2009年 | 461篇 |
2008年 | 1089篇 |
2007年 | 1447篇 |
2006年 | 1526篇 |
2005年 | 1476篇 |
2004年 | 1524篇 |
2003年 | 1500篇 |
2002年 | 1256篇 |
2001年 | 514篇 |
2000年 | 514篇 |
1999年 | 331篇 |
1998年 | 151篇 |
1997年 | 60篇 |
1996年 | 61篇 |
1995年 | 53篇 |
1994年 | 41篇 |
1993年 | 49篇 |
1992年 | 38篇 |
1991年 | 35篇 |
1990年 | 50篇 |
1989年 | 37篇 |
1988年 | 30篇 |
1987年 | 32篇 |
1986年 | 34篇 |
1985年 | 34篇 |
1984年 | 38篇 |
1983年 | 44篇 |
1982年 | 53篇 |
1981年 | 58篇 |
1980年 | 43篇 |
1979年 | 40篇 |
1978年 | 34篇 |
1977年 | 41篇 |
1975年 | 28篇 |
1974年 | 27篇 |
1972年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Allergic angiitis and granulomatosis (Churg-Strauss syndrome) is one of the rare form of idiopathic (primary) vasculitis. It is characterized by asthma, blood hypereosinophilia and typical microscopic features: nectrotizing vasculitis, tissue infiltration by eosinophils and extravasal granulomas. We present an autopsy case of 55-years old man with Churg-Strauss syndrome complicated by eosinophilic myocarditis. 相似文献
72.
The incidence of asthma and other allergic diseases continues to increase. In addition to genetic factors, environmental influences are thought to play an important role. The aim of this study was to identify factors that influence and drive the atopic march from atopic sensitization to asthma in children from Lód?. METHODS: 800 atopic children, aged 5-18 years, were included to our study. Parents filled in questionnaires and gave interviews about their children's diseases. 405 (43%) children have diagnosis of asthma. RESULTS: A significant association was observed between asthma and male sex, parents' history of atopy, parental highest school grade, maternal smoking during pregnancy, maternal chronic disease (especially chronic renal diseases), maternal allergen-sensitizing diet during breast-feeding, increased exposure to indoor humidity and moulds. Similar effect was seen for episodes of wheeze occurring in the first 3 years of life as followed: wheezing during an airway infection, wheezing not connected with respiratory tract infection, wheezing not related with physical exercise. Child's daycare attendance (nursery school) was associated with decreased risk of asthma. 相似文献
73.
Górecka D Bednarek M Kisło A Zalewska A Czechowska U Jedrzejczak M Zieliński J 《Pneumonologia i alergologia polska》2001,69(11-12):617-625
COPD is one of the leading causes of mortality and increased morbidity in developed world. In advanced disease it also imposes an important economic burden on societies. The main etiologic factor for COPD is tobacco smoking. The aim of the study was to asses if the awareness of airflow obstruction combined together with a minimal antismoking advice in middle aged smokers increases the quitting rate. Out of smokers participating in mass spirometric screening for COPD in five polish towns, we invited 734 (300 with airflow limitation and 247 with normal lung function) for a follow-up. During the second visit, at one year, spirometry was performed and smoking status was assessed. Non-smoking was validated with carbon monoxide measurements in exhaled breath. Patients who did not come for the follow-up visit were considered as smokers. Of 734 smokers invited, 543 (74%) presented for the follow-up visit. All smokers tried to modify the habit. Number of cigarettes smoked at one year was reduced by -5.5 (p < 0.001) in patients with airflow limitation and -2.2 (ns) in smokers with normal lung function. One year quit rate in smokers with airflow limitation was 11.1% vs 7.6% in smokers with normal lung function (ns). When the calculation was made for those who had the follow-up the quit rates were 15.1% vs 9.9% (p < 0.05). Cessation of smoking was correlated with lung function. Those smokers who stopped smoking permanently or tried to quit had lower FEV1 (p < 0.01) and FEV1/FVC (p < 0.05), than those who continued to smoke. 相似文献
74.
Zieliński J Czajkowska-Malinowska M Sankowski Z Kisło A Krawczyk K Skucha W Zalewska A Remiszewski W Kachel T Cynowska B Jedrzejczak M Lichota I Czechowska U Trawińska E Bednarek M 《Pneumonologia i alergologia polska》2000,68(5-6):217-225
COPD is the most frequent chronic lung disease in Poland. The disease is however under-diagnosed, especially at the early stages. The aim of the study was to assess the efficacy of spirometric screening for COPD in middle aged smokers. Informations on causes and symptoms of COPD were disseminated in mass media in 14 large cities. Subject aged over 39 and with smoking history of > 10 packyears were invited for a free spirometry in local chest clinic. However, everyone attending had the spirometry performed. Spirometry was performed according to ATS recommendations. Airway obstruction (AO) was diagnosed when FEV1/FVC < 85% of N and categorised as mild (FEV1 > 70% of N), moderate (FEV1 50-69% of N) or severe (FEV1 < 50% of N). Spirometry was accompanied by an antismoking advice. RESULTS: 12.781 subjects were screened (mean age 52 +/- 12 years, 57% males). In 8.269 subjects who complied with inclusion criteria AO was diagnosed in 29.8% (mild in 10.9%, moderate in 12% and severe in 6.9%). In smokers < 40 years of age and a history of < 10 packyears AO was found in 8.8% (mild in 6.0%, moderate in 1.8% and severe in 1.0%). CONCLUSION: Mass spirometry is an effective and easy method for early detection of COPD. 相似文献
75.
Adhesion molecules and their ligands in nasal polyps of aspirin-hypersensitive patients. 总被引:1,自引:0,他引:1
Maciej Kupczyk Izabela Kupry? Marian Danilewicz Ma?gorzata Bocheńska-Marciniak Anna Murlewska Pawe? Górski Piotr Kuna 《Annals of allergy, asthma & immunology》2006,96(1):105-111
BACKGROUND: Chronic inflammation with tissue eosinophilia plays a key role in the pathogenesis of asthma and nasal polyps in patients with aspirin hypersensitivity. OBJECTIVE: To evaluate the expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule I (ICAM-1) and their ligands (the integrins lymphocyte function-associated antigen 1 and very late-activation antigen 4 [VLA-4]) in nasal polyps of patients with aspirin hypersensitivity compared with aspirin-tolerant individuals. METHODS: Immunohistochemical studies were performed using a peroxidase method and monoclonal antibodies on 6-microm-thick cryostat sections cut from frozen polyps collected during elective surgery from 21 aspirin-sensitive and 23 aspirin-tolerant patients. RESULTS: The mean +/- SD values of the semiquantitatively evaluated immunoexpression of ICAM-1, VCAM-1, and VLA-4 were significantly increased in patients with aspirin hypersensitivity compared with aspirin-tolerant patients (1.7 +/- 0.8 vs 0.9 +/- 0.8, P < .003; 1.8 +/- 0.8 vs 0.8 +/- 0.8, P < .001; and 2.2 +/- 0.7 vs 1.3 +/- 0.7, P < .001, respectively), whereas the mean +/- SD values of the expression of lymphocyte function-associated antigen 1 did not differ significantly (2.4 +/- 0.5 vs 2.2 +/- 0.9; P = .57). We found a correlation between the immunoexpression of VCAM-1 and its ligand VLA-4 in all studied tissue samples (r = 0.4; P < .02). CONCLUSIONS: In nasal polyps of aspirin-hypersensitive patients, up-regulation of the adhesion molecules ICAM-1 and VCAM-1 and the integrin VLA-4 may play an important role in the development of chronic eosinophilic inflammation. 相似文献
76.
Wańkowska M Lerrant Y Wójcik-Gładysz A Starzec A Counis R Polkowska J 《Journal of chemical neuroanatomy》2002,23(2):133-142
Neuropeptide Y (NPY) is a putative neuroregulator of the reproductive axis in the central nervous system. In this study we evaluated the effects of central infusion of exogenous NPY on the secretory activity of pituitary gonadotrophic cells in prepubertal lambs. Immature female Merino sheep (n=12) were infused of Ringer solution (control) or 50 microg of NPY to the third ventricle for 5 min and then slaughtered 3 h later. Immunoreactive luteinizing hormone (LH) and follicle stimulating hormone (FSH) cells were localised by immunohistochemistry using antibody raised against LHbeta and FSHbeta. Messenger RNA analyses were performed by in situ hybridisation using sense and antisense riboprobes produced from beta subunits of LH and FSH cDNA clones. The results were generated by computer image analysis to determine the area fraction occupied by immunoreactive and/or hybridising cells and optical density for immunostaining and hybridisation signal. LH in the blood plasma was determined by radioimmunoassay. It was found, that in the lambs infused with NPY the area fraction and optical density for immunoreactive LH cells and mRNA LHbeta-expressing cells increased significantly (P<0.001), compared to the vehicle-infused animals. The concentration of LH in the blood plasma did not differ between control and treated groups. The NPY infusions had no effect on the immunoreactivity of FSH cells or on expression of mRNA for FSHbeta. In conclusion we suggest that NPY may be an important component of mechanisms stimulating the synthesis and storage but not the release of LH in the pituitary gonadotrophs from prepubertal female sheep. In addition, this effect is specific for LH, no such effect was apparent on FSH. 相似文献
77.
Małgorzata Niezgódka Joanna Mikulska Maciej Ugorski Janusz Boratyński Józef Lisowski 《Molecular immunology》1981,18(3):163-172
Characterization of the human placental membrane receptor for human 125I-IgG is described. The receptor bound specifically both monomers and aggregates of human IgG. Human colostral IgA, bovine, sheep, pig, and horse IgG were not bound. No effect of pH in the range 6.6–7.4, ionic strength in the range 0.1–0.5, and temperature between 4 and 45°C on the binding was found. A water-soluble fraction containing the active receptor (glycoprotein fraction-PGP) was obtained from the placental membranes using lithium diiodosalicylate. The solubilized receptor interacted with IgG better at 4°C than at 20°C or 37°C. The results on replacement of monomeric IgG by aggregated IgG, and vice versa, suggest that both monomers and aggregates of human IgG, were bound to the same receptor sites. The apparent association constant for monomeric human IgG was 0.86 ± 0.2 × 107 mole?1, and 2.0 ± 0.16 × 1015 IgG molecules were bound per l mg of the membrane protein. Formaldehyde (0.1%), 2-mercaptoethanol (50 mM), and periodate (4 mM) showed no effect on the binding properties of the membrane-bound and on the solubilized receptor, as well. Higher concentrations of periodate (10 mM or 20 mM) decreased the binding of IgG to membranes but showed no effect on the water-soluble receptor. Both the membrane-bound and the solubilized receptor were sensitive to papain. Pronose abolished the receptor activity after prolonged proteolysis only. Neuraminidase did not affect the activity of the receptor. The decrease of the binding activity of the membrane-bound receptor by trypsin and phospholipase C was due to a release of a material containing an active receptor. No effect of trypsin or phospholipase C on the activity of solubilized receptor was observed. The results obtained suggest a protein character of the placental Fc receptor. After electrophoresis of 125I-labeled solubilized receptor in polyacrylamide gel in the presence of SDS, 2 major protein peaks with molecular weights of 74,000 and 104,000 and 3 minor peaks with molecular weights of 56,000, 144,000, and 163,000 were found. 相似文献
78.
Rutkowski R Moniuszko T Stasiak-Barmuta A Kosztyła-Hojna B Alifier M Rutkowski K Tatarczuk-Krawiel A 《Archivum immunologiae et therapiae experimentalis》2003,51(6):421-428
CD80 and CD86 seem to play an important role in the allergen-induced secretion of interleukin (IL)-5 and IL-13. Up to now, the expressions of CD80 (B7.1) and CD86 (B7.2) on monocytes and the kinetics of the expression of these molecules on lipopolysaccharide-stimulated monocytes in nonatopic asthma have not been defined. Using monoclonal antibodies, we have compared the expressions of CD80 (B7.1) and CD86 (B7.2) on the monocytes of healthy persons and nonatopic asthmatic patients. We have also assessed the effect of CD80 and CD86 inactivation on IL-4 and interferon (IFN)-gamma production in nonatopic asthmatics and healthy subjects. We found that a low expression of CD80 (1.64 +/- 0.65 vs. 3.53 +/- 1.43%) and a moderate expression of CD86 (41.25 +/- 13.4 vs. 49.46 +/- 11.49%) on the studied monocytes were characteristic for asthma. In nonatopic asthma patients inactivation of CD80 or CD86 blockade significantly reduced IFN-gamma production by T lymphocytes (p < 0.02; p < 0.03). In both the studied groups, anti-CD80 antibodies did not diminish T lymphocyte production of IL-4. However, anti-CD86 antibodies significantly (p < 0.04) reduced the IL-4 concentration in culture supernatants. Our results confirm that both the CD80 and CD86 molecules play an important role in the maintenance and amplification of the inflammatory process. It suggests that in the inflammatory process that occurs in nonatopic bronchial asthma, Th1 as well as Th2 lymphocytes are equally important. 相似文献
79.
J. Marcinkiewicz M. Mak M. Bobek R. Biedroń A. Białecka M. Koprowski E. Kontny W. Maśliński 《Inflammation research》2005,54(1):42-49
Objective and Design: The myeloperoxidase system of neutrophils generates chlorinating and brominating oxidants in vivo. The major haloamines of the system are taurine chloramine (TauCl) and taurine bromamine (TauBr). It has been demonstrated in vitro that TauCl exerts both antiinflammatory and anti-bacterial properties. Much less is known about TauBr. The present study was conducted to compare bactericidal and immunoregulatory capacity of TauBr with that of the major chlorinating oxidants: HOCl and TauCl. Moreover, the effect of nitrites and H2O2 on TauBr activity was investigated.Materials: TauBr was prepared by reaction of HOBr with taurine. The reaction was monitored by UV absorption spectra.Methods: Bactericidal activity of TauBr, TauCl and HOCl was tested by incubation of E. coli with the compounds and determined by the pour-plate method. To test the anti-inflammatory activity the compounds were incubated with LPS and IFN- stimulated murine peritoneal macrophages. The production of following mediators was measured: nitrites by Griess reaction; TNF-, IL-6, IL-10, IL-12p40 using capture ELISA. In some experiments the compounds were incubated with either nitrites or H2O2.Results: In our experimental set-up TauBr and HOCl exerted strong bactericidal effects on E. coli (MBC = 110 M and 8 M, respectively), while TauCl (< 1000 M) did not kill test bacteria. However, both, TauBr and TauCl, at noncytotoxic concentrations (< 300 M) inhibited the cytokine and nitric oxide production by macrophages. H2O2 completely abolished the biological activities of TauBr but not those of TauCl. Nitrites did not affect any activity of TauBr or TauCl while they diminished the HOCl– mediated bacterial killing.Conclusion: TauBr, despite very low concentration of Br– in body fluids, may support TauCl and HOCl in the regulation of inflammatory response and in killing of bacteria by neutrophils. However, TauBr activity in vivo will depend on the presence of H2O2 and possible other mediators of inflammation which can compete with target molecules for TauBr.Received 16 August 2004; returned for revision 16 September 2004; accepted by A. Falus 13 October 2004 相似文献
80.
Hawryłkiewicz I Pałasiewicz G Pływaczewski R Sliwiński P Zieliński J 《Pneumonologia i alergologia polska》2000,68(1-2):37-43
We studied pulmonary haemodynamics and nocturnal desaturation in 17 patients with an overlap syndrome (OS), all males, mean age 51.4 +/- 8.3 years, mean BMI 37 +/- 4.2 kg/m2. Diagnosis of COPD was based on pts history, clinical examination, lung function tests and chest radiography. Spirometry showed: FVC 2.7 +/- 0.7 L (59 +/- 16% N), FEV1 1.5 +/- 0.7 L (43 +/- 16% N), FEV1% FVC 54 +/- 13%, Raw 0.58 +/- 0.4 kP.s/L, RV 3.3 +/- 1.2 L (144 +/- 51% N), TLC 6.6 +/- 1.3 L (100 +/- 14% N) and RV% TLC (49.5 +/- 12.1%. Arterial blood gas values were: PaO2 56.9 +/- 9.5 mmHg, PaCO2 46.9 +/- 9.8 mmHg, pH 7.37 +/- 0.05. Mean apnoea/hypopnoea index (AHI) was 63.9 +/- 18.9. Pulmonary haemodynamics at rest (Swan Ganz thermodilution catheter) were: mean pulmonary artery pressure (PAP-SP) 24.2 +/- 7.4 mmHg, mean pulmonary wedge pressure (PW-SP) was 9.1 +/- 7.3 mmHg, cardiac output (CO-SP) was 5.6 +/- 2.3 L/min. and pulmonary vascular resistance (PVR) was 229 +/- 97 dyn.sec.cm-5. During exercise (40 Watts, 7 mins, in 8 pts) PAP rose from 19 +/- 6 mmHg to 41.2 +/- 15.1 mmHg, PW rose from 7.4 +/- 7.2 mmHg to 11 +/- 10.2 mmHg, CO rose from 5.8 +/- 2.7 L/min to 12.7 +/- 2.4 L/min. Overnight pulse oximetry showed: mean oxygen saturation (SaO2 mean) 80.2 +/- 8.5%, minimal saturation (SaO2 min) was 50.7 +/- 19.7%. Time spent in desaturation SaO2 < 90% (T 90) was 76.9 +/- 25.7%. We conclude that pts with OS have resting pulmonary hypertension and elevated PVR. During low grade exercise the rise in PAP was highly abnormal. Statistical analysis showed no correlations between nocturnal SaO2 and diurnal pulmonary haemodynamics data. 相似文献