全文获取类型
收费全文 | 1222篇 |
免费 | 37篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 31篇 |
妇产科学 | 89篇 |
基础医学 | 165篇 |
口腔科学 | 4篇 |
临床医学 | 76篇 |
内科学 | 281篇 |
皮肤病学 | 14篇 |
神经病学 | 131篇 |
特种医学 | 13篇 |
外科学 | 120篇 |
综合类 | 20篇 |
预防医学 | 67篇 |
眼科学 | 13篇 |
药学 | 181篇 |
中国医学 | 2篇 |
肿瘤学 | 46篇 |
出版年
2023年 | 2篇 |
2022年 | 34篇 |
2021年 | 56篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 25篇 |
2014年 | 37篇 |
2013年 | 51篇 |
2012年 | 84篇 |
2011年 | 122篇 |
2010年 | 56篇 |
2009年 | 38篇 |
2008年 | 81篇 |
2007年 | 77篇 |
2006年 | 91篇 |
2005年 | 83篇 |
2004年 | 87篇 |
2003年 | 74篇 |
2002年 | 73篇 |
2001年 | 8篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 11篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1265条查询结果,搜索用时 15 毫秒
1.
Kamil Torres Anna Torres Grzegorz J. Staśkiewicz Andrzej Chrościcki Tadeusz Łoś Ryszard Maciejewski 《Surgical endoscopy》2009,23(9):2117-2123
Background Surgical procedures enhance production of pro- and anti-inflammatory cytokines and angiogenic factors that play a pivotal
role in the immunological response to surgical trauma and take part in the pathogenesis of tumor growth and adhesions formation.
The purpose of the study was to access the influence of low-pressure CO2 pneumoperitoneum on the inflammatory and angiogenic responses during the postoperative period after laparoscopy.
Methods The study group consisted of 40 patients, operated on due to cholelithiasis using standard-pressure (n = 20) and low-pressure (n = 20) CO2 pneumoperitoneum. Serum concentration of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF)-A, and
endostatin were measured before and at 6, 24, and 48 h after surgery with commercially available enzyme-linked immunosorbent
assay (ELISA).
Results Concentrations of IL-6 increased significantly after the operations in both groups. No differences were observed between the
groups in regards to IL-6, IL-8, and IL-10 levels. Concentrations of VEGF-A measured at 6 and 48 h were significantly lower
in patients who underwent laparoscopies performed with low-pressure pneumoperitoneum. No significant variations were observed
in endostatin serum concentration. Concentrations of the studied parameters were not influenced by duration of surgery or
by age, gender, or body mass index (BMI) of the patients.
Conclusions The results obtained in our study do not show any significant differences between studied operative procedures with regards
to systemic inflammatory response. Changes in the concentrations of VEGF-A and endostatin observed in the studied population
may suggest this technique is more favorable with regards to angiogenesis process intensity, along with all its consequences
and implications. 相似文献
2.
Franciszek Burdan Zofia Siezieniewska Ryszard Maciejewski Barbara Madej Elzbieta Radzikowska Zbigniew Wojtowicz 《Experimental and toxicologic pathology》2002,53(6):453-459
The aim of the study was to establish the influence of short-time omeprazole administration on liver function and morphology. Omeprazole was administered intraperitoneally, twice daily, for 3 days to male Wistar rats in two doses: 0.571 mg/kg and 5.71 mg/kg. Control animals were treated with physiological saline. Half of the animals were sacrificed 12 hours after the last injection. The remaining rats were raised for another 6 weeks, without any xenobiotics, and sacrificed on the 47th day of the experiment. The activity of free and bound fractions of hepatic acid phosphatase, beta-galactosidase, beta-N-acetyl-glucosaminidase, cathepsin B, D and L, lipase, and sulphatase were determined spectrophotometrically in homogenates of the liver. The liver sections were examined by light microscopy with hematoxylin-eosin, azan, and periodic acid-Schiff stains. Marginally significant (p < 0.1) differences in activity of free sulphatase fraction, and free and bound fractions of beta-galactosidase were found in animals exposed to the higher dose of omeprazole and sacrificed 12 hours after the last injection. Enzymatic profiles were normalised during the next 6 weeks. Histological evaluation revealed small degenerative and adaptive changes in all examined groups. It could be concluded that observed differences of hepatic lysosomal enzyme activities were the result of accompanied chemical-induced peritonitis as previously reported, and not a direct drug-toxic effect. 相似文献
3.
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
4.
Ryszard Grucza Yoshimi Miyamoto Yoshimi Nakazono 《European journal of applied physiology》1990,61(3-4):230-236
Summary Kinetics of cardiorespiratory response to dynamic (DE) and then to rhythmic-static exercise (RSE) was compared in nine male subjects exercising in an upright position on a cycle ergometer at an intensity of about 50 %
O2max and a mean pedalling frequency of 60 rpm over 5 min. Respiratory frequency (f
R), tidal volume (V
T), minute ventilation (
E), heart rate (f
c), stroke volume (SV), and cardiac output (Q
t) were measured continuously. The RSE caused a greater increase in f
R than DE, whereas V
T increased more during DE. The effect of reciprocal changes in f
R and V
T was that
E and its kinetics, expressed as a time constant (), did not differ between experimental situations. The ventilatory equivalent for O2 (
E:
O2) was greater for RSE (31.3) than for DE (23.0, P<0.01). Elevation of f
c was similar for both types of exercise. The SV increased suddenly at the beginning of DE from 54 ml to 74 ml and then decreased to the end of exercise. At the onset of RSE only a moderate increase in SV was observed, from 56 ml to 62 ml, and then SV remained stable. The DE caused a greater and faster increase in Q
t (4.20 l · min–1, for equal to 16.1s) than RSE (3.25 l · min–1, for equal to 57.0s, P<0.05 and P<0.002, respectively). Total peripheral resistance was almost 40% greater for RSE than for DE. No relationship was found between Q
t and VE at the first 15 s of both types of exercise. It is concluded that the kinetics of
E did not depend on to kinetics of Q
t in the exercising subjects. This finding contradicts the hypothesis of cardiodynamic hyperpnoea indicating an importance of neurogenic factors, mediated either centrally or peripherally, in fast cardiorespiratory responses to exercise. 相似文献
5.
Korona R 《Research in microbiology》2004,155(5):301-310
Yeast has proven to be a very useful model organism for studying eukaryotic cell functions. Its applicability for population and quantitative genetics is less well known. Among its advantages is the ease of screening for mutants. The present paper reviews experiments aimed at estimating the parameters of spontaneous mutations deleterious to fitness. The rate of deleterious mutation was found to be moderately high. A large fraction of detectable mutants were lethal; among the non-lethal mutants, the least harmful ones dominated. Deleterious mutations, and especially the lethal ones, were generally very well masked by wild-type alleles when in heterozygous loci. The negative effects of mutations were much stronger under stressful than under benign conditions. Interactions between loci with deleterious mutations did alter their fitness, but no strong overall effect of synergism or antagonisms was observed. 相似文献
6.
Wieslaw W. Pawlik Piotr Gustaw Eugene D. Jacobson Ryszard Sendur Krzysztof Czarnobilski 《Pflügers Archiv : European journal of physiology》1995,429(3):301-305
It has long been recognized that intestinal blood flow increases at mealtimes. Mesenteric hyperaemia is also evoked by activation of sensory peptidergic nerves. Our studies explored the possible role of endogenous nitric oxide (NO) in the rat intestinal vasodilator response to luminal instillation of an oleic acid plus bile mixture before and after acute intrajejunal instillation of capsaicin and after chronic pretreatment with capsaicin. In anaesthetized rats we measured jejunal blood flow (BF) with an ultrasonic Doppler flowmeter and systemic arterial pressure (AP) with a pressure transducer. Intestinal perfusion with 80 mM oleic acid in bile increased BF by 98±12%. Instillation of 4 mg of capsaicin into the jejunal lumen initially increased BF by 42±9% but was followed by vasoconstriction. Inhibition of NO synthase with 25 mg/kg i.v. N-nitro-L-arginine (L-NNA) decreased BF by 27±5% and increased AP by 37±11%. After treatment with L-NNA and after acute and chronic administration of capsaicin, the bile-oleate-induced maximal increases in BF above control levels were 42±7%, 65±12%, and 58±8%, respectively. The observed inhibitory effect of L-NNA on the intestinal hyperaemic response to the bile-oleate mixture was reversed by pretreatment with L-arginine (100 mg/kg i.V.). In capsaicin pretreated rats the subsequent bile-oleate-induced hyperaemia was reduced in magnitude but the inhibitory effects of L-NNA were proportionately the same as in animals not receiving capsaicin. These findings support the hypothesis that NO is involved with bile-oleate-induced mesenteric hyperaemia. 相似文献
7.
Ryszard Andrzej Jedrychowski Jerzy Andrzej Sokal Jadwiga Chmielnicka 《Archives of toxicology》1984,55(3):195-198
Rats were subjected to 4 h continuous or intermittent exposure to vinyl chloride (VC) at different time-weighted average concentrations (15, 50, 150, 500 and 15,000 mg/m3). Hepatic non-protein sulfhydryl content (NPSH) and excretion of thiodiglycolic acid (TdGA) in urine were determined. VC at concentrations from 50 mg/m3 to 15,000 mg/m3 caused a dose-dependent depression of NPSH, but no difference in the magnitude of this depression induced by continuous or intermittent exposure at the same average concentration of VC was noted. At average concentrations of 50 mg/m3 and 150 mg/m3, the urinary excretion of TdGA under continuous exposure did not differ from that under intermittent exposure, whereas at VC concentrations of 500 mg/m3 and 15,000 mg/m3 it was higher following continuous exposure. 相似文献
8.
ucja Zieliska-Tomczak Piotr Przymuszaa Szymon Tomczak Izabela Krzyko-Pieczka Ryszard Marciniak Magdalena Cerbin-Koczorowska 《Nutrients》2021,13(6)
The growing popularity of health education on social media indicates the need for its appropriate evaluation. This paper aims to present the potential of the Kirkpatrick Model (KM) with New World Kirkpatrick Model (NWKM) additions to evaluate the nutritional education provided by dieticians via Instagram. Instagram profiles of ten dieticians providing nutritional education for their followers were analyzed in March and April 2021. The study sample included profiles of both macro- and micro-influencers. The analyzed quantitative data included Instagram Engagement Rate and the number of likes and comments per post. The qualitative analysis of the comments was performed following the theoretical framework provided by the KM and NWKM. Collected data showed followers’ satisfaction, commitment, and relevance of the presented content, fulfilling the Level 1 of NWKM. Level 2 of NWKM was represented by 4 out of 5 dimensions (knowledge, attitude, confidence, commitment). No comments were found only for skills. Both Levels 3 (Behavior) and 4 (Results) of the KM were met. However, the use of the NWKM for them seems limited. The KM can be used to evaluate nutritional education on social media. The NWKM additions seem applicable mostly for Levels 1 and 2. 相似文献
9.
Increased plasma tumour necrosis factor (TNF) concentration correlates with mortality in sepsis. We suggested that pentoxifylline (PTXF), which is known to inhibit TNF production, may improve survival and attenuate clinical symptoms of sepsis in neonates. Plasma TNF levels were evaluated in 29 newborn infants with sepsis. Patients were randomly assigned into two groups, receiving PTXF in a dose of 5 mg/kg per hour for 6 h or placebo (saline), on 3 successive days. Both groups were subjected to the same conventional therapy. TNF was evaluated before and after PTXF or placebo administration on the 1 st and 3rd days of therapy. There was a statistically significant decrease in plasma TNF level in the PTXF group when the values before the first and after the last PTXF infusion were compared [mean: 671.5 pg/ml; SD: 438; med: 729.6 vs mean: 41.0 pg/ml; SD: 64.1; med: 11.5;P<0.000004]. In the placebo group, decrease was not significant [mean: 633.0 pg/ml SD: 488.6; med: 618.9 vs 246.9 pg/ml; SD: 243.9; med: 191.0]. A significantly higher plasma TNF level, evaluated after the last PTXF infusion, was found in the placebo group [246,9 pg/ml vs 41.0 pg/ml;P<0.001]. Only one of four infants with signs of shock in the placebo group survived, whereas all of five newborns with symptoms of shock in the PTXF group survived [P<0.04]. An increased incidence of metabolic acidosis [P<0.05], necrotizing enterocolitis [P<0.04] and renal insufficiency [P<0.05] was observed in infants in the placebo group.Conclusion PTXF inhibits production of TNF and may have therapeutic value in the treatment of premature infants with sepsis complicatea by shock. 相似文献
10.
Jacek Pika Micha Kwany Adam Filipkowski Ryszard Buczyski Mirosaw A. Karpierz Urszula A. Laudyn 《Materials》2022,15(21)
We study an optical device designed for converting the polarized Gaussian beam into an optical vortex of tunable polarization. The proposed device comprised a set of three specially prepared nematic liquid crystal cells and a nano-spherical phase plate fabricated from two types of glass nanotubes. This device generates a high-quality optical vortex possessing one of the multiple polarization states from the uniformly polarized input Gaussian beam. Its small size, simplicity of operation, and electrical steering can be easily integrated into the laboratory and industrial systems, making it a promising alternative to passive vortex retarders and spatial light modulators. 相似文献