全文获取类型
收费全文 | 2551篇 |
免费 | 172篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 46篇 |
妇产科学 | 42篇 |
基础医学 | 393篇 |
口腔科学 | 23篇 |
临床医学 | 247篇 |
内科学 | 525篇 |
皮肤病学 | 42篇 |
神经病学 | 189篇 |
特种医学 | 57篇 |
外科学 | 356篇 |
综合类 | 20篇 |
一般理论 | 2篇 |
预防医学 | 315篇 |
眼科学 | 43篇 |
药学 | 229篇 |
中国医学 | 9篇 |
肿瘤学 | 180篇 |
出版年
2023年 | 27篇 |
2022年 | 72篇 |
2021年 | 103篇 |
2020年 | 57篇 |
2019年 | 64篇 |
2018年 | 107篇 |
2017年 | 73篇 |
2016年 | 81篇 |
2015年 | 87篇 |
2014年 | 99篇 |
2013年 | 166篇 |
2012年 | 209篇 |
2011年 | 231篇 |
2010年 | 82篇 |
2009年 | 104篇 |
2008年 | 141篇 |
2007年 | 137篇 |
2006年 | 114篇 |
2005年 | 108篇 |
2004年 | 94篇 |
2003年 | 97篇 |
2002年 | 76篇 |
2001年 | 26篇 |
2000年 | 25篇 |
1999年 | 27篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1993年 | 9篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 14篇 |
1970年 | 6篇 |
1969年 | 7篇 |
排序方式: 共有2737条查询结果,搜索用时 15 毫秒
121.
Andreas Eich Veronika Urban Marek Jutel Jiri Vlcek Jae Jeong Shim Vasiliy I. Trofimov 《COPD》2017,14(5):476-483
Interleukin (IL)-17A may be an underlying factor in the pathophysiology of chronic obstructive pulmonary disease (COPD). Anti-IL-17 monoclonal antibodies have been used successfully in treating several immune-mediated inflammatory diseases. This phase 2, randomized, placebo-controlled, double-blind, parallel-group, proof-of-concept study is the first clinical study evaluating the efficacy and safety of the anti-IL-17A monoclonal antibody CNTO 6785 in patients with symptomatic moderate-to-severe COPD. Patients were treated with CNTO 6785 (n = 93) or placebo (n = 94) intravenously at Weeks 0, 2, and 4 (induction), then Weeks 8 and 12, and followed till Week 24. The primary efficacy endpoint was the change from baseline in pre-bronchodilator percent-predicted forced expiratory volume in 1 second at Week 16. Samples were collected at all visits for pharmacokinetic (PK) evaluation, and standard safety assessments were performed. The mean difference in the primary efficacy endpoint between CNTO 6785 and placebo was not statistically significant (?0.49%; p = 0.599). No other efficacy endpoints demonstrated clinically or statistically significant differences with CNTO 6785 compared with placebo. CNTO 6785 was generally well tolerated; no major safety signals were detected. The most frequently reported treatment-emergent adverse events were infections and infestations; however, no notable differences were observed between CNTO 6785 and placebo in terms of rates of infections. PK results suggested that the steady state of serum CNTO 6785 concentration was reached within 16 weeks. These results suggest that IL-17A is unlikely to be a dominant driver in the pathology of, or a viable therapeutic target for, COPD. ClinicalTrials.gov Identifier: NCT01966549; EudraCT Identifier: 2012-003607-36. 相似文献
122.
Veronika Olšovcová 《Applied radiation and isotopes》2010,68(7-8):1383-1387
The response of radionuclide calibrators for radionuclides with high abundances of high energy X-rays is very sensitive to changes in the source geometry. The magnitude of this effect was explored for Bqmetr (Konsorcium BQM, CR) calibrators with 123I, 111In and 153Sm in several vial and syringe geometries. Dependencies of chamber responses on solution volume and container position were calculated using MCNP transport code. The possibility of usage of an additional copper filter to reduce chamber sensitivity was studied and found to be suitable. 相似文献
123.
124.
Veronika Zámbó Laura Simon-Szabó Péter Szelényi éva Kereszturi Gábor Bánhegyi Miklós Csala 《World journal of hepatology》2013,5(10):550-557
Obesity due to excessive food intake and the lack of physical activity is becoming one of the most serious public health problems of the 21st century. With the increasing prevalence of obesity, non-alcoholic fatty liver disease is also emerging as a pandemic. While previously this pathophysiological condition was mainly attributed to triglyceride accumulation in hepatocytes, recent data show that the development of oxidative stress, lipid peroxidation, cell death, inflammation and fibrosis are mostly due to accumulation of fatty acids, and the altered composition of membrane phospholipids. In fact, triglyceride accumulation might play a protective role, and the higher toxicity of saturated or trans fatty acids seems to be the consequence of a blockade in triglyceride synthesis. Increased membrane saturation can profoundly disturb cellular homeostasis by impairing the function of membrane receptors, channels and transporters. However, it also induces endoplasmic reticulum stress via novel sensing mechanisms of the organelle’s stress receptors. The triggered signaling pathways in turn largely contribute to the development of insulin resistance and apoptosis. These findings have substantiated the lipotoxic liver injury hypothesis for the pathomechanism of hepatosteatosis. This minireview focuses on the metabolic and redox aspects of lipotoxicity and lipoapoptosis, with special regards on the involvement of endoplasmic reticulum stress responses. 相似文献
125.
Impaired hemorheology in patients with postmastectomy lymphedema 总被引:2,自引:0,他引:2
Manuela P. Djavanmard Ilse Michl M. Korpan Barbara Fazeny Alexandra C. Budinsky Elmar Wiesinger Georg Weinländer Michael Binder Margot Püspök Christoph C. Zielinski Veronika Fialka Renate Koppensteiner Christine Marosi 《Breast cancer research and treatment》1996,38(3):283-288
Lymphedema of the arm is one of the most disabling and serious complications of breast cancer. Apart from tumor infiltration or fibrosis of lymphatic pathways, little is known about factors favoring the development of lymphedema. In the present study, we investigated the impact of rheologic parameters, e.g. red cell aggregation (EA) and plasma viscosity (PV), and of capillary morphology and capillary flow in patients with breast cancer with (n = 18) and without (n = 18) lymphedema. Patients with lymphedema showed a significant increase of red cell aggregation (p < 0.001) that indicates a systemic component of lymphedema and might offer a possibility of prevention and therapy of this condition. A hitherto unclassified protein factor favoring red cell aggregation and lymphedema might be postulated. 相似文献
126.
Sarnatskaya VV Lindup WE Niwa T Ivanov AI Yushko LA Tjia J Maslenny VN Korneeva LN Nikolaev VG 《Biochemical pharmacology》2002,63(7):1287-1296
The ability of albumin to bind drugs and other lipophilic organic acids is decreased in chronic renal failure by the accumulation of albumin-bound uraemic toxins such as hippuric acid, indoxyl sulphate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF). This furan acid is the most highly bound and is not removed by haemodialysis. The inhibitory effects of these three uraemic toxins on the interaction of three marker ligands sodium octanoate (for medium chain fatty acids), salicylic acid and phenol red (bilirubin site/site I) with albumin have been investigated by differential scanning microcalorimetry and flow microcalorimetry. CMPF was the most potent inhibitor and its binding site coincided with that of bilirubin (site I). Indoxyl sulphate binds to the site for medium-chain fatty acids and tryptophan (site II) and hippuric acid, the weakest inhibitor, inhibited binding to the salicylic acid site. 相似文献
127.
Butterweck V Nahrstedt A Evans J Hufeisen S Rauser L Savage J Popadak B Ernsberger P Roth BL 《Psychopharmacology》2002,162(2):193-202
RATIONALE: Hypericum perforatum L. (St. John's wort; SJW) is one of the leading psychotherapeutic phytomedicines and great effort has been devoted to clarifying its mechanism of action. OBJECTIVE: We have undertaken a comprehensive analysis of several pure compounds isolated from the crude extract to gain further insight into the molecular actions of various substituents of SJW. METHODS: We characterized the in vitro pharmacology of the naphthodianthrones hypericin and pseudohypericin, the phloroglucinol derivative hyperforin, and several flavonoids at 42 biogenic amine receptors and transporters using the resources of the National Institute of Mental Health Psychoactive Drug Screening Program. RESULTS: The biflavonoid amentoflavone significantly inhibited binding at serotonin (5-HT(1D), 5-HT(2C)), D(3)-dopamine, delta-opiate, and benzodiazepine receptors. The naphthodianthrone hypericin had significant activity at D(3)- and D(4)-dopamine receptors and beta-adrenergic receptors. With the exception of the D(1)-dopamine receptor, the phloroglucinol derivative hyperforin was less active than other SJW constituents tested on all screened receptors. CONCLUSION: Our present in vitro data clearly show that several pure substances in SJW are potential CNS psychoactive agents and may contribute to the antidepressant efficacy of the plant in a complex manner. Our data also reveal novel and heretofore unexpected interactions of pure compounds in SJW at a number of GPCRs, transporters, and ion channels. We hypothesize that additive or synergistic actions of different single compounds may be responsible for the antidepressant efficacy of SJW. These results and this general approach may impact our understanding of phytomedicines in general and H. perforatum specifically. 相似文献
128.
129.
Sexual dimorphism in renal ischemia-reperfusion injury in rats: possible role of endothelin 总被引:4,自引:0,他引:4
Müller V Losonczy G Heemann U Vannay A Fekete A Reusz G Tulassay T Szabó AJ 《Kidney international》2002,62(4):1364-1371
BACKGROUND: Postischemic organ dysfunction is influenced by gender and sexual steroids. METHODS: To compare the susceptibility of the kidney to postischemic failure between sexes, the left vascular pedicle was clamped for 50 minutes in anesthetized male and female Wistar rats. Survival rate, renal and systemic hemodynamics and renal prepro-endothelin (pp-ET) mRNA expression were measured. RESULTS: Eight percent of males as compared to 75% of females survived for more than 7 days. Previous orchidectomy of mature rats or sexual immaturity improved the rate of 7 day survival to 67% and 58%, respectively, as compared to intact males (P < 0.05). Estradiol treatment of mature male animals also resulted in a significantly better survival. Ovariectomy, sexual immaturity or testosterone treatment had no impact on the course of renal failure in females. The early postischemic recovery of renal blood flow was delayed due to a dramatic increase in renal vascular resistance in male versus female rats. The expression of pp-ET gene in the kidneys was increased at 5 minutes following reperfusion and was significantly higher 2 hours after ischemia in males, but not in females. Pretreatment with the endothelin A receptor antagonist LU 135252 provided indistinguishable survival rates in intact male and female rats after warm renal ischemia. CONCLUSION: Female rats enjoy relative protection against postischemic renal failure. Furthermore, in intact males the effects of androgens upon ischemic kidney damage seem to be mediated by endothelin-induced vascular changes. 相似文献
130.
Ahluwalia N de Silva A Atukorala S Weaver V Molls R 《The American journal of clinical nutrition》2002,75(2):289-294
BACKGROUND: Assessing iron status continues to be challenging in field situations. Spot methods developed for analyzing ferritin from serum or plasma samples that are spotted and dried on filter paper have been shown to provide reliable and accurate iron-status assessments. However, the spot methods are based on samples from venous serum or plasma and have not been evaluated in field settings. OBJECTIVE: We evaluated the validity of analyzing ferritin to assess iron status by using venous and capillary dried-serum-spot (DSS) samples by the spot method compared with using serum ferritin by the traditional method in a field setting. DESIGN: Venous and capillary blood was obtained from healthy schoolchildren (n = 100; +/- SD age: 8.9 +/- 0.3 y) in Colombo, Sri Lanka. To prepare DSS samples, we aliquoted precisely 20 microL serum per spot on filter paper, air-dried the spots, and placed them in airtight plastic bags until analysis by the spot ferritin method with the use of cellulase from Trichoderma reesei at 2 wk after collection. Venous serum (100 microL) was frozen until ferritin determination by traditional radioimmunoassay. RESULTS: Venous and capillary DSS ferritin values correlated strongly with traditional serum ferritin values (r = 0.88 and 0.86, respectively; P = 0.0001). The geometric means (+/- 1 SD) for venous and capillary DSS ferritin and traditional ferritin were 26.9 (15.3-47.4), 33.9 (20.9-54.8), and 33.1 (18.6-58.8) microg/L, respectively, and were not significantly different. Venous and capillary DSS methods on average (+/- SD) yielded ferritin values that were 5.8 +/- 10.1 microg/L lower and 0.1 +/- 9.4 microg/L higher, respectively, than serum ferritin values obtained with the traditional method. CONCLUSIONS: Capillary and venous DSS methods for analyzing ferritin provide accurate tools for assessing iron status. Furthermore, capillary DSS ferritin is a practical means of detecting iron deficiency in field settings. 相似文献