全文获取类型
收费全文 | 5486篇 |
免费 | 609篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 83篇 |
儿科学 | 154篇 |
妇产科学 | 131篇 |
基础医学 | 954篇 |
口腔科学 | 90篇 |
临床医学 | 642篇 |
内科学 | 1211篇 |
皮肤病学 | 46篇 |
神经病学 | 478篇 |
特种医学 | 206篇 |
外国民族医学 | 1篇 |
外科学 | 776篇 |
综合类 | 107篇 |
一般理论 | 4篇 |
预防医学 | 553篇 |
眼科学 | 41篇 |
药学 | 344篇 |
中国医学 | 19篇 |
肿瘤学 | 269篇 |
出版年
2021年 | 104篇 |
2020年 | 62篇 |
2019年 | 90篇 |
2018年 | 84篇 |
2017年 | 83篇 |
2016年 | 86篇 |
2015年 | 101篇 |
2014年 | 120篇 |
2013年 | 167篇 |
2012年 | 258篇 |
2011年 | 252篇 |
2010年 | 135篇 |
2009年 | 138篇 |
2008年 | 249篇 |
2007年 | 238篇 |
2006年 | 264篇 |
2005年 | 256篇 |
2004年 | 252篇 |
2003年 | 224篇 |
2002年 | 198篇 |
2001年 | 206篇 |
2000年 | 188篇 |
1999年 | 182篇 |
1998年 | 75篇 |
1997年 | 51篇 |
1996年 | 54篇 |
1995年 | 49篇 |
1994年 | 37篇 |
1993年 | 35篇 |
1992年 | 150篇 |
1991年 | 130篇 |
1990年 | 120篇 |
1989年 | 121篇 |
1988年 | 120篇 |
1987年 | 110篇 |
1986年 | 102篇 |
1985年 | 92篇 |
1984年 | 78篇 |
1983年 | 65篇 |
1982年 | 49篇 |
1981年 | 42篇 |
1980年 | 47篇 |
1979年 | 74篇 |
1978年 | 35篇 |
1977年 | 36篇 |
1976年 | 35篇 |
1975年 | 38篇 |
1974年 | 39篇 |
1973年 | 50篇 |
1972年 | 37篇 |
排序方式: 共有6109条查询结果,搜索用时 675 毫秒
271.
Alexandersen S Quan M Murphy C Knight J Zhang Z 《Journal of comparative pathology》2003,129(4):268-282
Foot-and-mouth disease virus (FMDV) can be spread by a variety of mechanisms and the rate of spread, the incubation period and the severity of disease depend on a multitude of parameters, including the strain of virus, the dose received, the route of introduction, the animal species and the husbandry conditions. More knowledge with regard to these parameters is urgently needed to improve resource-efficient disease control. This report describes detailed studies of FMDV load, excretion and transmission in pigs infected with FMDV O UKG 2001, O TAW 1997 and C Noville virus and in cattle infected with the O UKG 2001 virus to facilitate use of a "FMDV load framework" for the assessment of transmission risks. Virus replicated rapidly in pigs and cattle exposed by direct contact. The mean incubation period was around 3-4 days for cattle-to-cattle and 1-3 days for pig-to-pig transmission, depending on the intensity of contact. The results confirmed that a strong relation exists between dose and length of incubation period. Clinical disease was severe in pigs but relatively mild in inoculated cattle; contact infection of cattle appeared to increase the severity of lesions. FMDV RNA was recovered in nasal and mouth swabs from inoculated animals soon after they developed a viraemia and probably reflected the early production and excretion of virus. FMDV RNA in nasal and mouth swabs from contact animals could be detected several days before they showed other signs of infection, indicating the possibility of detecting exposed animals during the incubation period. FMDV RNA could also be detected in swab samples after the viraemic phase. This may have represented background environmental virus that had been trapped in the respiratory tract and mouth. Alternatively, it may have indicated a somewhat slower clearance or half-life of viral RNA or an extended low level of FMDV replication at these sites. The pattern of FMDV RNA concentrations in pigs was closely similar to that in cattle, but the amounts of FMDV RNA were higher. 相似文献
272.
Neurogenic heterotopic ossification is a process of abnormal bone formation of multi-factorial aetiology. It occurs at varying sites to produce deformity and restriction of joint movement, and has a major impact on physical ability. There is extensive literature on the medical management of heterotopic ossification, but the role of physiotherapy is poorly described.This article aims to illustrate the importance of proactive physiotherapy in the team management and treatment of this condition. The authors show that physiotherapy is not contra-indicated in the presence of neurogenic heterotopic ossification and illustrate how interventions for improving range of movement can be used. The authors suggest that integrated team management was essential to the successful outcomes in these complex cases. 相似文献
273.
274.
Leaves or infusions of feverfew, Tanacetum parthenium, have long been used as a folk remedy for fever, arthritis and migraine, and derived products are widely available in U.K. health food shops. Previous reports have suggested interactions with arachidonate metabolism. Crude chloroform extracts of fresh feverfew leaves (rich in sesquiterpene lactones) and of commercially available powdered leaves (lactone-free) produced dose-dependent inhibition of the generation of thromboxane B2 (TXB2) and leukotriene B4 (LTB4) by ionophore- and chemoattractant-stimulated rat peritoneal leukocytes and human polymorphonuclear leukocytes. Approximate IC50 values were in the range 5-50 micrograms/mL, and inhibition of TXB2 and LTB4 occurred in parallel. Isolated lactones (parthenolide, epoxyartemorin) treated with cysteine (to neutralize reactive alpha-methylene butyrolactone functions of the sesquiterpenes). Inhibition of eicosanoid generation appeared to be irreversible but not time-dependent. We conclude that feverfew contains a complex mixture of sesquiterpene lactone and non-sesquiterpene lactone inhibitors of eicosanoid synthesis of high potency, and that these biochemical actions may be relevant to the claimed therapeutic actions of the herb. 相似文献
275.
Margaret A. DiGuardo Jaime I. Davila Rory A. Jackson Asha A. Nair Numrah Fadra Kay T. Minn Mazen A. Atiq Shabnam Zarei Joseph H. Blommel Shannon M. Knight Jin Jen Bruce W. Eckloff Jesse S. Voss Kandelaria M. Rumilla Sarah E. Kerr Dora M. Lam-Himlin Andrew M. Bellizzi Rondell P. Graham Kevin C. Halling 《The Journal of molecular diagnostics : JMD》2021,23(5):555-564
276.
Kate E Ryan Claire Glister Pat Lonergan Finian Martin Phil G Knight Alexander CO Evans 《Journal of ovarian research》2008,1(1):1-13
Background
The intracellular signalling mechanisms that regulate ovarian follicle development are unclear; however, we have recently shown differences in the Akt and Erk signalling pathways in dominant compared to subordinate follicles. The aim of this study was to investigate the effects of inhibiting Akt and Erk phosphorylation on IGF- and gonadotropin- stimulated granulosa and theca cell function in vitro, and on follicle development in vivo.Methods
Bovine granulosa and theca cells were cultured for six days and stimulated with FSH and/or IGF, or LH in combination with PD98059 (Erk inhibitor) and/or LY294002 (Akt inhibitor) and their effect on cell number and hormone secretion (estradiol, activin-A, inhibin-A, follistatin, progesterone and androstenedione) determined. In addition, ovarian follicles were treated in vivo with PD98059 and/or LY294002 in ewes on Day 3 of the cycle and follicles were recovered 48 hours later.Results
We have shown that gonadotropin- and IGF-stimulated hormone production by granulosa and theca cells is reduced by treatment with PD98059 and LY294002 in vitro. Furthermore, treatment with PD98059 and LY294002 reduced follicle growth and oestradiol production in vivo.Conclusion
These results demonstrate an important functional role for the Akt and Erk signalling pathways in follicle function, growth and development. 相似文献277.
Restoration of E-cadherin/beta-catenin expression in pancreatic cancer cells inhibits growth by induction of apoptosis 总被引:3,自引:0,他引:3
BACKGROUND: beta-Catenin is a component of the E-cadherin/catenin adhesion complex that maintains epithelial cell integrity. We have previously observed decreased beta-catenin expression in both human pancreatic cancer cell lines and primary tumors. To determine the significance of this finding with respect to pancreatic carcinogenesis, this study evaluated the effects of restoring expression of beta-catenin with and without E-cadherin in pancreatic cancer cells. METHODS: MiaPaca-2 cells were stably transfected with full-length cDNAs for beta-catenin, E-cadherin, or a mutated E-cadherin lacking the beta-catenin-binding domain. Doubly transfected cell clones containing beta-catenin and either E-cadherin or deleted E-cadherin were also selected. Assays for cell adhesion, cell cycle profile, motility, and apoptosis were performed. RESULTS: Cell clones expressing beta-catenin alone or beta-catenin and deleted E-cadherin did not differ significantly from the parental cell lines in any of the assays performed. In contrast, MiaPaca-2 cell clones expressing both beta-catenin and E-cadherin showed tight adhesion, decreased cell growth, and a significantly increased apoptotic index as compared to the parental line or singly transfected clones. CONCLUSIONS: MiaPaca-2 cells undergo apoptosis at a significantly increased rate after restoration of the E-cadherin/beta-catenin adhesion complex. This increase in apoptosis is dependent on the ability of E-cadherin to bind beta-catenin. Loss of beta-catenin expression may therefore provide pancreatic cancer cells with a growth advantage that contributes to tumor progression. 相似文献
278.
Eric L Knight Meir J Stampfer Eric B Rimm Susan E Hankinson Gary C Curhan 《Nephrology, dialysis, transplantation》2003,18(8):1549-1554
BACKGROUND: The impact of moderate alcohol consumption on renal function has important public health implications given the high prevalence of alcohol use. Experimentally, alcohol may adversely affect renal function, but clinical data are limited and no large, prospective studies have examined this issue. METHODS: In a prospective study of 1658 nurses enrolled in the Nurses' Health Study, we sought to determine if there was an association between moderate alcohol consumption and rate of decline in renal function. Daily alcohol intake was measured in 1990, 1994 and 1998 using a detailed questionnaire. Maximum daily alcohol intake was measured in 1988. Creatinine, measured from blood samples provided in 1989 and 2000, was used to estimate glomerular filtration rate (GFR) and creatinine clearance (CCr). RESULTS: Compared to individuals with no alcohol intake, the odds ratios (ORs) for developing a >or=25% estimated GFR decline were: 0.98 (95% CI: 0.72-1.32) for 0.1-4.9 g/day, 0.83 (95% CI: 0.56-1.21) for 5-14.9 g/day and 0.81 (95% CI: 0.50-1.31) for 15-59.9 g/day. For women with hypertension (n = 726), the ORs for a >or=25% estimated GFR decline were: 0.98 (95% CI: 0.53-1.21) for 0.1-4.9 g/day, 0.62 (95% CI: 0.34-1.12) for 5-14.9 g/day and 0.53 (95% CI: 0.25-1.12) for 15-59.9 g/day. CONCLUSIONS: Moderate alcohol consumption had no substantial adverse effect on renal function in women over an 11 year follow-up period. 相似文献
279.
280.