全文获取类型
收费全文 | 23044篇 |
免费 | 1625篇 |
国内免费 | 266篇 |
专业分类
耳鼻咽喉 | 366篇 |
儿科学 | 356篇 |
妇产科学 | 270篇 |
基础医学 | 3898篇 |
口腔科学 | 306篇 |
临床医学 | 2027篇 |
内科学 | 4403篇 |
皮肤病学 | 911篇 |
神经病学 | 1500篇 |
特种医学 | 1774篇 |
外科学 | 2735篇 |
综合类 | 81篇 |
一般理论 | 2篇 |
预防医学 | 901篇 |
眼科学 | 651篇 |
药学 | 2346篇 |
中国医学 | 337篇 |
肿瘤学 | 2071篇 |
出版年
2024年 | 10篇 |
2023年 | 115篇 |
2022年 | 370篇 |
2021年 | 866篇 |
2020年 | 455篇 |
2019年 | 626篇 |
2018年 | 733篇 |
2017年 | 639篇 |
2016年 | 969篇 |
2015年 | 1404篇 |
2014年 | 1580篇 |
2013年 | 1742篇 |
2012年 | 2395篇 |
2011年 | 2181篇 |
2010年 | 1470篇 |
2009年 | 1153篇 |
2008年 | 1477篇 |
2007年 | 1354篇 |
2006年 | 1180篇 |
2005年 | 1091篇 |
2004年 | 818篇 |
2003年 | 685篇 |
2002年 | 557篇 |
2001年 | 152篇 |
2000年 | 147篇 |
1999年 | 100篇 |
1998年 | 94篇 |
1997年 | 81篇 |
1996年 | 66篇 |
1995年 | 34篇 |
1994年 | 35篇 |
1993年 | 26篇 |
1992年 | 40篇 |
1991年 | 42篇 |
1990年 | 24篇 |
1989年 | 26篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1976年 | 6篇 |
1973年 | 5篇 |
1971年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
Molecular mechanism for loss of visual cortical responsiveness following brief monocular deprivation
A dramatic form of experience-dependent synaptic plasticity is revealed in visual cortex when one eye is temporarily deprived of vision during early postnatal life. Monocular deprivation (MD) alters synaptic transmission such that cortical neurons cease to respond to stimulation of the deprived eye, but how this occurs is poorly understood. Here we show in rat visual cortex that brief MD sets in motion the same molecular and functional changes as the experimental model of homosynaptic long-term depression (LTD), and that prior synaptic depression by MD occludes subsequent induction of LTD. The mechanisms of LTD, about which there is now a detailed understanding, therefore contribute to visual cortical plasticity. 相似文献
92.
This study analyzed the expression of anti-islet autoantibodies and HLA-DR and -DQ genotypes in Korean children with type 1 diabetes mellitus (T1DM). The positivity of the anti-ICA512, anti-GAD65, and anti-insulin autoantibodies in the newly onset T1DM patients (n = 15) was 66.7%, 86.7%, and 46.7%, respectively, and all of them had one or more of the autoantibodies. HLA analysis showed higher frequencies of HLA-DRB1*0301, *0405, *09012 and -DQB1*0201, *0401, *03032 alleles in T1DM patients compared to controls (P(c) < 0.05). Because HLA-DQB1*0401, *03032 alleles carry aspartic acid at position 57 of DQB, susceptibility to T1DM in Korean children was not related to the presence of aspartic acid at position 57 of DQB1 locus. We suggest this unique HLA-DR, -DQ allele distribution might be an important factor for the low incidence of T1DM in Korea, and the combined anti-islet autoantibody assays could be valuable screening markers for the early detection of T1DM in Korea. 相似文献
93.
94.
Tetanus is uncommon in Korea due to the introduction of vaccination programs and advances in public health. A case of maternal tetanus occurred on the 9 day postpartum in a 29-yr-old woman, who had not received a 10-yr-booster of tetanus-diphtheria toxoid after receiving the primary series of tetanus-toxoid-containing vaccine. There has hitherto been no reports on maternal tetanus in Korea. This case illustrates that tetanus remains a medical problem, principally among non- and under-immunized adults. The only way to fully prevent this disease is to ensure adequate immunization in all adults. 相似文献
95.
Joon Young Song Seok Hoon Ha Sae Yoon Kee Hye Won Jeong Hee Jin Cheong Woo Joo Kim 《Journal of clinical virology》2007,38(2):149-152
BACKGROUND: Influenza vaccination is the primary method for preventing influenza and its severe complications. Healthcare workers (HCWs) are one of the priority groups for the influenza vaccination. OBJECTIVES: To determine whether healthy HCWs, who were vaccinated with the same subtype for the two previous years, could be given less priority for influenza immunization under the vaccine shortage. STUDY DESIGN: We measured hemagglutination-inhibition antibody titers from sequential serum samples in 50 pre-immune subjects and 50 age-matched vaccine-naive subjects: immediately prior to the administration of the vaccine, 4-6 weeks, and 6 months after the vaccination. RESULTS: Prevaccination titers were maintained above protective level and high protection rates were observed for all three strains in pre-immune subjects: A/H1N1, A/H3N2, and B strains. As for the sequential changes, the protection rates for all three strains still remained above 70% until 6 months following the vaccination. CONCLUSION: Skipping influenza vaccination for a year could be considered in healthy pre-immune HCWs under the epidemic of the same subtype as two previous years. 相似文献
96.
Effects of cGMP-dependent phosphorylation on rat and human connexin43 gap junction channels 总被引:6,自引:0,他引:6
Brenda R. Kwak Juan C. Sáez Ronald Wilders Marc Chanson Glenn I. Fishman Elliot L. Hertzberg David C. Spray Habo J. Jongsma 《Pflügers Archiv : European journal of physiology》1995,430(5):770-778
The effects of 8-bromoguanosine 3:5-cyclic monophosphate (8Br-cGMP), a membrane-permeant activator of protein kinase G (PKG), were studied on rat and human connexin43 (Cx43), the most abundant gap junction protein in mammalian heart, which were exogenously expressed in SKHep1 cells. Under dual whole-cell voltage-clamp conditions, 8Br-cGMP decreased gap junctional conductance (gj) in rat Cx43-transfected cells by 24.0±3.7% (mean±SEM, n=5), whereas gj was not affected in human Cx43-transfected cells by the same treatment. The relaxation of gj in response to steps in transjunctional voltage observed in rat Cx43 transfectants was best fitted with three exponentials. Time constants and amplitudes of the decay phases changed in the presence of 8Br-cGMP. Single rat and human Cx43 gap junction channels were resolved in the presence of halothane. Under control conditions, three single-channel conductance states (j) of about 20, 40–45 and 70 pS were detected, the events of the intermediate size being most frequently observed. In the presence of 8Br-cGMP, the
j distribution shifted to the lower size in rat Cx43 but not in human Cx43 transfectants. Immunoblot analyses of Cx43 in subconfluent cultures of rat Cx43 or human Cx43 transfectants showed that 8Br-cGMP did not induce changes in the electrophoretic mobility of Cx43 in either species. However, the basal incorporation of [32P] into rat Cx43 was significantly altered by 8Br-cGMP, whereas this incorporation of [32P] into human Cx43 was not affected. We conclude that 8Br-cGMP modulates phosphorylation of rat Cx43 in SKHep1 cells, but not of human Cx43. This cGMP-dependent phosphorylation of rat Cx43 is associated with a decreased gj, which results from both an increase in the relative frequency of the lowest conductance state and a change in the kinetics of these channels. 相似文献
97.
Pathogenicity of Treponema pallidum may depend upon the binding of Treponema pallidum to matrix proteins, especially to fibronectin. Infectious organism or cell to matrix interactions are mediated by a family of adhesion molecule receptors known as integrins. Once in the host, the pathogenic Treponema pallidumdum adheres to the vascular endothelium and readily penetrates surrounding tissues. Fibronectin plays an important role in the mediation of the attachment of Treponema pallidum to host cells, including endothelial cells. We found that the binding of Treponema pallidum to human dermal microvascular endothelial cells and to a glass surface coated with fibronectin is inhibited by the presence of arginine-glycine- aspartic acid (RGD), and analysis of the surface receptor revealed an antigenic similarity to an integrin molecule, namely alpha5. This ability to adhere to host endothelium and fibronectin is quite unique to T. pallidum among the treponemes, and may be a key pathogenic factor. 相似文献
98.
Min-Seok Rha Hye Won Jeong Jae-Hoon Ko Seong Jin Choi In-Ho Seo Jeong Seok Lee Moa Sa A Reum Kim Eun-Jeong Joo Jin Young Ahn Jung Ho Kim Kyoung-Ho Song Eu Suk Kim Dong Hyun Oh Mi Young Ahn Hee Kyoung Choi Ji Hoon Jeon Jae-Phil Choi Eui-Cheol Shin 《Immunity》2021,54(1):44-52.e3
- Download : Download high-res image (218KB)
- Download : Download full-size image
99.
Kim CK Kim SW Park CS Kim BI Kang H Koh YY 《The Journal of allergy and clinical immunology》2003,112(1):64-71
BACKGROUND: The pathogenetic basis for the relationship between acute bronchiolitis and asthma has not yet been completely elucidated. OBJECTIVE: The aim of this study was to compare these 2 diseases in terms of their patterns of airway cytokine response (T(H)1 or T(H)2). METHODS: By using a bronchoalveolar lavage (BAL) technique, this study investigated the cytokine levels of BAL fluid in children with acute asthma who had no identifiable respiratory syncytial virus (RSV) infection (n = 18) and in infants with acute bronchiolitis caused by RSV (n = 22). Comparisons were made with normal control subjects (n = 14). IFN-gamma (T(H)1) and IL-4 and IL-5 (T(H)2) levels were measured in concentrated BAL fluids by means of ELISA. RESULTS: The IL-5 level (P <.001) and IL-5/IFN-gamma ratio (P <.001) were significantly increased in the asthmatic group with no identifiable RSV infection and in the RSV-induced bronchiolitis group compared with values in the control group. When infants in the bronchiolitis group were divided into eosinophil-positive and eosinophil-negative subgroups, the eosinophil-positive subgroup had significantly increased IL-5 levels (P <.001) and IL-5/IFN-gamma ratios (P <.01) compared with those in the control group, but similar cytokine responses were not induced in the eosinophil-negative subgroup. The percentage of BAL eosinophils correlated significantly with levels of BAL IL-5 in both the asthma group (r = 0.80, P =.000) and the bronchiolitis group (r = 0.82, P =.000). CONCLUSIONS: These findings suggest that a subgroup of the RSV-induced bronchiolitis group results in a T(H)2-type response, and this could provide a valuable framework to explain the link between RSV-induced bronchiolitis and asthma. 相似文献
100.