全文获取类型
收费全文 | 2931篇 |
免费 | 232篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 106篇 |
妇产科学 | 35篇 |
基础医学 | 380篇 |
口腔科学 | 58篇 |
临床医学 | 362篇 |
内科学 | 461篇 |
皮肤病学 | 11篇 |
神经病学 | 239篇 |
特种医学 | 281篇 |
外科学 | 484篇 |
综合类 | 75篇 |
一般理论 | 1篇 |
预防医学 | 153篇 |
眼科学 | 40篇 |
药学 | 324篇 |
肿瘤学 | 176篇 |
出版年
2021年 | 37篇 |
2019年 | 38篇 |
2018年 | 53篇 |
2017年 | 26篇 |
2016年 | 28篇 |
2015年 | 46篇 |
2014年 | 50篇 |
2013年 | 85篇 |
2012年 | 133篇 |
2011年 | 126篇 |
2010年 | 108篇 |
2009年 | 120篇 |
2008年 | 126篇 |
2007年 | 143篇 |
2006年 | 124篇 |
2005年 | 106篇 |
2004年 | 94篇 |
2003年 | 93篇 |
2002年 | 106篇 |
2001年 | 73篇 |
2000年 | 76篇 |
1999年 | 63篇 |
1998年 | 72篇 |
1997年 | 67篇 |
1996年 | 69篇 |
1995年 | 58篇 |
1994年 | 57篇 |
1993年 | 40篇 |
1992年 | 41篇 |
1991年 | 62篇 |
1990年 | 61篇 |
1989年 | 65篇 |
1988年 | 51篇 |
1987年 | 47篇 |
1986年 | 52篇 |
1985年 | 57篇 |
1984年 | 41篇 |
1983年 | 32篇 |
1982年 | 36篇 |
1981年 | 18篇 |
1980年 | 30篇 |
1979年 | 41篇 |
1978年 | 30篇 |
1977年 | 30篇 |
1976年 | 24篇 |
1975年 | 25篇 |
1974年 | 28篇 |
1973年 | 22篇 |
1971年 | 19篇 |
1970年 | 21篇 |
排序方式: 共有3199条查询结果,搜索用时 15 毫秒
71.
72.
Oberyszyn TM; Conti CJ; Ross MS; Oberyszyn AS; Tober KL; Rackoff AI; Robertson FM 《Carcinogenesis》1998,19(3):445-455
The beta2 integrin (CD 18/CD 11 a, b, c) family of proteins mediate
adherence of leukocytes to vascular endothelium and the associated ligand,
intercellular adhesion molecule-1 (ICAM-1; CD 54), interacts with beta2
integrin proteins to allow transendothelial migration of leukocytes into
sites of inflammation. The present study examines the function of these
proteins in a murine model of acute cutaneous inflammation induced
following topical application of 12-O- tetradecanoylphorbol-13-acetate
(TPA) to the dorsal epidermis of SENCAR mice and in a model of skin
multistage carcinogenesis. At 24 h following topical application of TPA to
the dorsal epidermis of mice, dermal leukocytes expressed higher levels of
beta2 integrin protein compared with the lower levels of beta2 integrin
protein expression by peripheral blood leukocytes. ICAM-1 protein was
localized to epidermal keratinocytes and vascular endothelium in
TPA-treated skin and to proliferating papilloma cells. Intravenous (i.v.)
injection of either 50 microg anti-beta2 integrin antibody alone or in
combination with anti-ICAM-1 antibody significantly inhibited both
TPA-stimulated neutrophil infiltration into the dermis (P < 0.001) and
myeloperoxidase (MPO) activity (P < 0.03 anti-beta2 integrin antibody; P
< 0.01 anti- beta2 integrin + ICAM-1 adhesion molecule antibodies), but
had no effect on TPA-induced epidermal hyperplasia. In addition, injection
of either anti-ICAM-1 adhesion molecule antibody alone (P < 0.004) or in
combination with anti-beta2 integrin antibody (P < 0.001) significantly
inhibited TPA-induced production of 7,8-dihydroxy-2'-deoxyguanosine (8-
OHdG) immunoreactive proteins by epidermal keratinocytes. Beta2
integrin/ICAM-1 adhesion molecules work in concert to regulate migration,
retention and functional activation of leukocytes within the dermis during
TPA-induced skin inflammation and within stromal tissue of papillomas that
form during multi-stage carcinogenesis. Agents that inhibit these
receptor/ligand interactions may be useful in defining the roles of
specific cell populations in cutaneous inflammation and multistage
carcinogenesis and may also have potential as anti-promoting and
anti-progression agents.
相似文献
73.
Bolontrade MF; Stern MC; Binder RL; Zenklusen JC; Gimenez-Conti IB; Conti CJ 《Carcinogenesis》1998,19(12):2107-2113
In this study we have analyzed the vascular response induced in the two-
stage carcinogenesis model in SENCAR mice. The role of angiogenesis has not
been explored in this model, which is the paradigm of multistage
carcinogenesis and a model for neoplastic lesions derived from exophytic
premalignant lesions (e.g. colon carcinoma, bladder papilloma). We
investigated if angiogenesis is involved in the formation of papillomas and
in the progression from papilloma to carcinoma. To this end we analyzed the
vasculature of normal and hyperplastic skin, focal epidermal hyperplasias
that are precursors of papillomas, papillomas at different stages and
squamous cell carcinomas. We also analyzed the vascularization of
papillomas induced in two strains of mice that differ in their
susceptibility to malignant progression. We show here that angiogenesis is
turned on in the earliest stages of papilloma formation. In late stages,
regardless of state of progression, the predominant response is an increase
in the size of blood vessels. Thus, in the SENCAR mouse model,
representative of exophytic tumors, the angiogenesis switch is a very early
event, probably mechanistically related to the development of the primarily
exophytic lesions. Therefore, the density of blood vessels cannot be used
as a predictor of malignant progression in this model.
相似文献
74.
The effects of interleukin-10 in hemorrhagic shock 总被引:6,自引:0,他引:6
Karakozis S Hinds M Cook JW Kim D Provido H Kirkpatrick JR 《The Journal of surgical research》2000,90(2):109-112
BACKGROUND: Interleukin-10 (IL-10) counteracts the effects of the proinflammatory cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF). Experimental data suggest that inhibition of these proinflammatory cytokines improves outcome in sepsis, endotoxemia, necrotizing pancreatitis, and other severe inflammatory states. We hypothesized that the administration of IL-10 would attenuate the release of proinflammatory cytokines after severe hemorrhagic shock. METHODS: To test our hypothesis, male Sprague-Dawley rats (N = 20) were divided into control and experimental groups. We induced hemorrhagic shock by removing a sufficient quantity of blood to maintain a mean arterial pressure of 50 mm Hg or less for 120 min. The animals were then resuscitated with shed blood and an equal volume of 0.9% saline. The experimental group received 10,000 units of IL-10 at the initiation of shock. Serum IL-1, IL-6, TNF, and lactate were measured at baseline, after 120 min of shock, and 60 min after resuscitation. The rats were followed for 72 h to calculate survival. RESULTS: Similar levels of hypoperfusion were obtained in both groups as demonstrated by lactate levels and amount of shed blood. The survival rate (70%) was the same in both groups. Serum levels of IL-1 and IL-6 were not significantly different between the two groups, although there was a trend toward IL-6 suppression. TNF, however, was significantly lower in the IL-10-treated group at the end of shock (Wilcoxon test, P < 0. 025). CONCLUSION: Administration of IL-10 suppresses the TNF surge observed after severe hemorrhagic shock. 相似文献
75.
Clinical cerebral microdialysis: a methodological study 总被引:21,自引:0,他引:21
Hutchinson PJ O'Connell MT Al-Rawi PG Maskell LB Kett-White R Gupta AK Richards HK Hutchinson DB Kirkpatrick PJ Pickard JD 《Journal of neurosurgery》2000,93(1):37-43
OBJECT: Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals' neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC). METHODS: A specially designed bolt was used to conduct two adjacent microdialysis catheters into the frontal cortex of patients with head injury or poor-grade subarachnoid hemorrhage who were receiving ventilation. One reference catheter (10-mm membrane, perfused with Ringer's solution at 0.3 microl/minute) was constant for all studies. The other catheter was varied in terms of membrane length (10 mm or 30 mm), perfusion fluid (Ringer's solution or normal saline), and flow rate (0.1-1.5 microl/minute). The effect of freezing the samples on substance concentration was established by on-line analysis and then repeated analysis after storage at -70 degrees C for 3 months. Samples assayed with the bedside enzyme analyzer were reassessed using HPLC for the determination of glutamate concentrations. CONCLUSIONS: Two adjacent microdialysis catheters that were identical in membrane length, perfusion fluid, and flow rate showed equivalent results. Variations in perfusion fluid and freezing and thawing of samples did not result in differences in substance concentration. Catheter length had a significant impact on substance recovery. Variations in flow rate enabled the relative recovery to be calculated using a modification of the extrapolation-to-zero-flow method. The recovery was approximately 70% at 0.3 microl/minute and 30% at 1 microl/minute (10-mm membrane) for all analytes. Glutamate results obtained with the enzyme analyzer showed good correlation with those from HPLC. 相似文献
76.
Jill M. Steiner Kristen K. Patton Jordan M. Prutkin James N. Kirkpatrick 《Journal of pain and symptom management》2018,55(2):530-534
A 63-year-old man with end-stage ischemic cardiomyopathy presented with incessant ventricular tachycardia. He had been hospitalized multiple times in the past year for severe heart failure. As he approached end of life and was regularly receiving defibrillator shocks, his care team recommended deactivation of his implantable cardioverter-defibrillator. However, his family did not wish to allow deactivation, reporting a religious obligation to prolong his life, regardless of the risk of suffering. The patient was unable to adequately participate in the decision-making process. An implantable cardioverter-defibrillator can serve to avoid sudden death but may lead to a prolonged death from heart failure. This possibility forces the examination of values regarding prolongation of life, sometimes producing disagreement among stakeholders. Although ethical consensus holds that defibrillator deactivation is legal and ethical, disagreements about life prolongation may complicate decision making. The ethical, technical, and medical complexity involved in this case speaks to the need for clear, prospective communication involving the patient, the patient's family, and members of the care team. 相似文献
77.
78.
Kirkpatrick B. Fergus Thomas W. Gaither Nima Baradaran David V. Glidden Andrew J. Cohen Benjamin N. Breyer 《The journal of sexual medicine》2019,16(8):1236-1245
BackgroundSexual dysfunction is common among adults and takes a toll on quality of life for both men and women.AimTo determine whether higher levels of weekly cardiovascular exercise are protective against self-reported sexual dysfunction among men and women.MethodsWe conducted an international online, cross-sectional survey of physically active men and women between April and December 2016, assessing exercise activity categorized into sextiles of weekly metabolic equivalent-hours. Odds ratios (ORs) of sexual dysfunction for each activity sextile compared with the lowest sextile were calculated using multivariable logistic regression, controlling for age, body mass index, diabetes mellitus, tobacco/alcohol use, sport, and marital status.Main Outcome MeasuresFemale sexual dysfunction was defined as a score ≤26.55 on the Female Sexual Function Inventory and erectile dysfunction (ED) was defined as a score ≤21 on the Sexual Health Inventory for Men.Results3,906 men and 2,264 women (median age 41–45 and 31–35 years, respectively) met the inclusion criteria for the study. Men in sextiles 2–6 had reduced odds of ED compared with the reference sextile in adjusted analysis (Ptrend = .03), with an OR of 0.77 (95% CI = 0.61–0.97) for sextile 4 and 0.78 (95% CI = 0.62–0.99) for sextile 6, both statistically significant. Women in higher sextiles had a reduced adjusted OR of female sexual dysfunction (Ptrend = .02), which was significant in sextile 4 (OR = 0.70; 95% CI = 0.51–0.96). A similar pattern held true for orgasm dissatisfaction (Ptrend < .01) and arousal difficulty (Ptrend < .01) among women, with sextiles 4–6 reaching statistical significance in both.Clinical ImplicationsMen and women at risk for sexual dysfunction regardless of physical activity level may benefit by exercising more rigorously.Strengths & LimitationsStrengths include using a large international sample of participants with a wide range of physical activity levels. Limitations include the cross-sectional design, and results should be interpreted in context of the study population of physically active adults.ConclusionHigher cardiovascular exercise levels in physically active adults are inversely associated with ED by self-report in men and protective against female sexual dysfunction in women.Fergus KB, Gaither TW, Baradaran N, et al. Exercise Improves Self-Reported Sexual Function Among Physically Active Adults. J Sex Med 2019;16:1236–1245. 相似文献
79.
CJ Stewart ECL Marrs S Magorrian A Nelson C Lanyon JD Perry ND Embleton SP Cummings JE Berrington 《Acta paediatrica (Oslo, Norway : 1992)》2012,101(11):1121-1127
Aim: To describe gut colonization in preterm infants using standard culture and 16S gene rRNA profiling, exploring differences in healthy infants and those who developed NEC/late onset sepsis (LOS). Methods: Ninety‐nine stools from 38 infants of median 27‐week gestation were cultured; 44 stools from 27 infants had their microbial profiles determined by 16S. Ordination analyses explored effects of patient variables on gut communities. Results: Standard microbiological culture identified a mean of two organisms (range 0–7), DGGE 12 (range 3–18) per patient. Enterococcus faecalis and coagulase negative staphylococci (CONS) were most common by culture (40% and 39% of specimens). Meconium was not sterile. No fungi were cultured. Bacterial community structures in infants with NEC and LOS differed from healthy infants. Infants who developed NEC carried more CONS (45% vs 30%) and less Enterococcus faecalis (31% vs 57%). 16S identified Enterobacter and Staphylococcus presence associated with NEC/LOS, respectively. Conclusions: Important differences were found in the gut microbiota of preterm infants who develop NEC/LOS. The relationship of these changes to current practices in neonatal intensive care requires further exploration. 相似文献
80.