全文获取类型
收费全文 | 48513篇 |
免费 | 5057篇 |
国内免费 | 1488篇 |
专业分类
耳鼻咽喉 | 265篇 |
儿科学 | 1737篇 |
妇产科学 | 405篇 |
基础医学 | 6536篇 |
口腔科学 | 1378篇 |
临床医学 | 5145篇 |
内科学 | 10390篇 |
皮肤病学 | 1327篇 |
神经病学 | 2527篇 |
特种医学 | 850篇 |
外国民族医学 | 5篇 |
外科学 | 3627篇 |
综合类 | 7649篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 3095篇 |
眼科学 | 829篇 |
药学 | 4633篇 |
28篇 | |
中国医学 | 3270篇 |
肿瘤学 | 1357篇 |
出版年
2024年 | 182篇 |
2023年 | 1002篇 |
2022年 | 1195篇 |
2021年 | 2349篇 |
2020年 | 2233篇 |
2019年 | 1930篇 |
2018年 | 1850篇 |
2017年 | 2053篇 |
2016年 | 2152篇 |
2015年 | 1961篇 |
2014年 | 3494篇 |
2013年 | 3856篇 |
2012年 | 3501篇 |
2011年 | 3576篇 |
2010年 | 2731篇 |
2009年 | 2596篇 |
2008年 | 2429篇 |
2007年 | 2186篇 |
2006年 | 1943篇 |
2005年 | 1702篇 |
2004年 | 1368篇 |
2003年 | 1139篇 |
2002年 | 987篇 |
2001年 | 878篇 |
2000年 | 681篇 |
1999年 | 594篇 |
1998年 | 577篇 |
1997年 | 448篇 |
1996年 | 459篇 |
1995年 | 349篇 |
1994年 | 317篇 |
1993年 | 280篇 |
1992年 | 280篇 |
1991年 | 224篇 |
1990年 | 190篇 |
1989年 | 161篇 |
1988年 | 147篇 |
1987年 | 141篇 |
1986年 | 124篇 |
1985年 | 147篇 |
1984年 | 125篇 |
1983年 | 88篇 |
1982年 | 92篇 |
1981年 | 78篇 |
1980年 | 62篇 |
1979年 | 44篇 |
1978年 | 39篇 |
1977年 | 36篇 |
1976年 | 34篇 |
1974年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
71.
目的 :探讨血清透明质酸 (HA)、Ⅳ型胶原 (CIV)及层黏蛋白 (LN)联合检测对肝纤维化的诊断价值。方法 :采用酶联免疫法对健康人组 2 2例、急性肝炎组 10例、慢性肝炎组 10例、肝硬化组 2 5例及慢性重症肝炎组 10例 ,分别检测血清HA ,CIV及LN的水平 ;对肝硬化组三项指标分别检测和联合检测所得的敏感性、特异性及准确性进行比较。结果 :血清中HA ,CIV及LN的水平以肝硬化组和慢性重症肝炎组最高 ,均明显高于其它组 (P <0 0 1)。肝硬化组联合检测的敏感性高于单项检测的敏感性 ,但其特异性降低。结论 :联合检测HA ,CIV及LN可提高诊断肝纤维化敏感性 ,但特异性降低 ;其中HA +CIV的敏感性和特异性较高 ,为最优联合 相似文献
72.
Inhibition of the expression of lysyl oxidase and its substrates in cadmium-resistant rat fetal lung fibroblasts. 总被引:3,自引:0,他引:3
Yinzhi Zhao Song Gao Iih-Nan Chou Paul Toselli Phillip Stone Wande Li 《Toxicological sciences》2006,90(2):478-489
Copper (Cu)-dependent lysyl oxidase (LO) catalyzes crosslinking of collagen and elastin stabilizing the extracellular matrix (ECM). Chronic inhalation of cadmium (Cd), a toxic metal, induces emphysema. To probe mechanisms of Cd injury to the lung, we developed Cd-resistant (CdR) cells from rat fetal lung fibroblasts (RFL6) by chronic exposure to CdCl(2) from 1 to 40 microM and further examined their expressions of LO, LO substrates, and Cu-scavenging thiols. Levels of cellular thiols, metallothionein, and glutathione in CdR cells were elevated to 13.0- and 3.2-fold of parental controls, respectively, whereas LO mRNA and protein levels were markedly reduced in these cells, with catalytic activity declining to only 16% of the parental control. A conspicuous 52 kDa species rather then the normal 50 kDa proenzyme appeared in the CdR cell extract but not in the conditioned medium, which was codistributed with the endoplasmic reticulum marker [DiOC5(3)] within the cell, implying the Cd-induced 52 kDa species as a product of an abnormal LO-processing defect in secretion. Addition of Cu into CdR cell cultures enhanced the expression of LO mRNA, protein and catalytic activities reflecting limitation of Cu bioavailability for LO in these cells. With inhibition of LO, CdR cells also displayed downregulation of collagen and elastin, substrates of LO. Restoration of collagen synthesis by exposure of CdR cells to purified LO or Cu suggests that inhibition of LO and limitation of Cu cofactor by Cd, as key phenotype changes, accelerated collagen and elastin damage, a critical event pertinent to emphysema pathogenesis. 相似文献
73.
Manish Gautam Santanu Saha Sarang Bani A. Kaul Sanjay Mishra Dada Patil N.K. Satti K.A. Suri Sunil Gairola K. Suresh Suresh Jadhav G.N. Qazi Bhushan Patwardhan 《Journal of ethnopharmacology》2009
Ethnopharmacological relevance
Roots of Asparagus racemosus Willd (Shatavari in vernacular) are widely used in Ayurveda as Rasayana for immunostimulation, galactogogue as also in treatment of conditions like ulcers and cancer. Various studies have indicated immunomodulatory properties of Shatavari root extracts and formulations.Aim of the study
To study the effect of standardized Asparagus racemosus root aqueous extract (ARE) on systemic Th1/Th2 immunity of SRBC sensitized animals.Materials and methods
We used HPTLC to quantify steroidal saponins (Shatavarin IV, Immunoside®) and flow cytometry to study effects of ARE on Th1/Th2 immunity. SRBC specific antibody titres and DTH responses were also monitored as markers of Th2 and Th1 responses, respectively. We also studied lymphocyte proliferation. Cyclosporin, cyclophosphamide and levamisole were used as controls.Results
Treatment with ARE (100 mg/(kg b.w. p.o.)) resulted in significant increase of CD3+ and CD4/CD8+ percentages suggesting its effect on T cell activation. ARE treated animals showed significant up-regulation of Th1 (IL-2, IFN-g) and Th2 (IL-4) cytokines suggesting its mixed Th1/Th2 adjuvant activity. Consistent to this, ARE also showed higher antibody titres and DTH responses. ARE, in combination with LPS, Con A or SRBC, produced a significant proliferation suggesting effect on activated lymphocytes.Conclusion
The study suggests mixed Th1/Th2 activity of ARE supports its immunoadjuvant potential. 相似文献74.
Rodica Pop-Busui Jiang Lu Neuza Lopes Teresa L. Z. Jones and the BARI D Investigators 《Journal of the peripheral nervous system : JPNS》2009,14(1):1-13
Abstract We evaluated the associations between glycemic therapies and prevalence of diabetic peripheral neuropathy (DPN) at baseline among participants in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial on medical and revascularization therapies for coronary artery disease (CAD) and on insulin-sensitizing vs. insulin-providing treatments for diabetes. A total of 2,368 patients with type 2 diabetes and CAD was evaluated. DPN was defined as clinical examination score >2 using the Michigan Neuropathy Screening Instrument (MNSI). DPN odds ratios across different groups of glycemic therapy were evaluated by multiple logistic regression adjusted for multiple covariates including age, sex, hemoglobin A1c (HbA1c), and diabetes duration. Fifty-one percent of BARI 2D subjects with valid baseline characteristics and MNSI scores had DPN. After adjusting for all variables, use of insulin was significantly associated with DPN (OR = 1.57, 95% CI: 1.15–2.13). Patients on sulfonylurea (SU) or combination of SU/metformin (Met)/thiazolidinediones (TZD) had marginally higher rates of DPN than the Met/TZD group. This cross-sectional study in a cohort of patients with type 2 diabetes and CAD showed association of insulin use with higher DPN prevalence, independent of disease duration, glycemic control, and other characteristics. The causality between a glycemic control strategy and DPN cannot be evaluated in this cross-sectional study, but continued assessment of DPN and randomized therapies in BARI 2D trial may provide further explanations on the development of DPN. 相似文献
75.
76.
77.
L. Porto E. Hattingen U. Pilatus M. Kieslich B. Yan D. Schwabe F. E. Zanella H. Lanfermann 《Child's nervous system》2007,23(3):305-314
Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance
spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information
regarding cell membrane proliferation, neuronal damage, and energy metabolism.
Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential
diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions
located at the brainstem using Point-resolved spectroscopy sequences.
Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination
secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis
was confirmed by biopsy or by clinical follow-up.
Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative
lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role. 相似文献
78.
Fertility in Persons with Epilepsy: 1935–1974 总被引:18,自引:17,他引:1
Data from the Rochester-Olmsted County Medical Records Linkage Project were utilized to assess fertility in persons with epilepsy. Population age-specific reproduction rates for Rochester residents for the years 1935-1974 were estimated using the number of live births from the Minnesota Department of Health Statistics and Vital Statistics of the U.S. for comparison with rates in affected persons. Overall, fertility rates were significantly reduced to 80% of expected for affected males and 85% for affected females. Individuals with partial seizures (simple and complex) were disadvantaged, whereas those with generalized onset were not. During the last 20 years of the study period, males were more disadvantaged than females. The male-female difference was greatest during the time of low population fertility (after 1965). Male deficits were more marked after diagnosis; female deficits were more marked before diagnosis. Differences in the proportion of ever-married person-years between the sexes only partially explain the observed differences. 相似文献
79.
A. Purohit S. Laffer† C. Metz-Favre A. Verot F. Kricek‡ R. Valenta† G. Pauli 《Clinical and experimental allergy》2005,35(2):186-192
BACKGROUND: Results from several studies indicate that the magnitude of immediate symptoms of type I allergy caused by allergen-induced cross-linking of high-affinity Fc epsilon receptors on effector cells (mast cells and basophils) is not always associated with allergen-specific IgE levels. OBJECTIVE: To investigate the association of results from intradermal skin testing, basophil histamine release and allergen-specific IgE, IgG1-4, IgA and IgM antibody levels in a clinical study performed in birch pollen-allergic patients (n = 18). METHODS: rBet v 1-specific IgEs were measured by quantitative CAP measurements and by using purified Fc epsilon RI-derived alpha-chain to quantify IgE capable of binding to effector cells. Bet v 1-specific IgG subclasses, IgA and IgM levels were measured by ELISA, and basophil histamine release was determined in whole blood samples. Intradermal skin testing was performed with the end-point titration method. RESULTS: Our study demonstrates on the molecular level that the concentrations of allergen-specific IgE antibodies capable of binding to Fc epsilon RI and biological sensitivities are not necessarily associated. A moderate association was found between cutaneous and basophil sensitivity. CONCLUSION: Our results highlight the quantitative discrepancies and limitations of the present diagnostic tools in allergy, even when using a single allergenic molecule. The quantity of allergen-specific serum IgE is only one component of far more complex cellular systems (i.e. basophil-based tests, skin tests) used as indirect diagnostic tests for IgE-mediated allergic sensitivity. 相似文献
80.
Objective To investigate the best way to control the blood sugar level during the perioperation of bone fracture patients with type 2 diabetes(T2DM).Methods Bone fracture patients with T2DM were randomly divided into three groups:continuous subcutaneous insulin infusion group(insulin aspart,group CSII,n=20),glargine treatment group(insulin aspart+insulin glargine,group GA,n=20),and NPH treatment(insulin aspart+rh-insulin,group NA,n=20).The levels of fasting plasma glucose(FPG)and the 2 hours postprandial glucose(2h PG),blood glucose fluctuation(BGF),insulin dosage(ID),good effective time(GET),incidence of hypoglycemia,dawn phenomenon and infection,average time of stitches removal(ATSR),average hospitalized length(AHL)of three groups were compared.Results FPG and 2hPG,ID in group CSII[(6.32±1.18)mmol/L,(7.72±1.53)mmol/L,(35.40±1.60)IU]and group GA [(6.25±0.88)mmol/L,(7.32±1.17)mmol/L,(36.20±0.80)IU]were significantly lower than those of group NA [(7.44±1.36)mmol/L,(8.52±0.76)mmol/L,(40.50±2.40)IU,all P<0.05],simulaneously,BGF,GET incidence of complications,ATSR,AHL of group CSII and GA were significantly lower than those of group NA(all P<0.05).There were not significant difference between group CSII and group GA.Compared with group CSII,group GA had less costs in-hospital and better practicability.Conclusion Both CSII and insulin glargine combined with insulin aspart can effectively,safely,rapidly and stablely control hyperglycemia.and might be the first choice to control blood sugar for bone fracture patients with T2DM in perioperation. 相似文献