全文获取类型
收费全文 | 5187篇 |
免费 | 237篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 86篇 |
儿科学 | 141篇 |
妇产科学 | 118篇 |
基础医学 | 1103篇 |
口腔科学 | 140篇 |
临床医学 | 472篇 |
内科学 | 717篇 |
皮肤病学 | 65篇 |
神经病学 | 449篇 |
特种医学 | 150篇 |
外科学 | 545篇 |
综合类 | 28篇 |
一般理论 | 1篇 |
预防医学 | 294篇 |
眼科学 | 181篇 |
药学 | 335篇 |
中国医学 | 4篇 |
肿瘤学 | 601篇 |
出版年
2018年 | 47篇 |
2015年 | 67篇 |
2014年 | 92篇 |
2013年 | 155篇 |
2012年 | 163篇 |
2011年 | 162篇 |
2010年 | 164篇 |
2009年 | 119篇 |
2008年 | 190篇 |
2007年 | 165篇 |
2006年 | 182篇 |
2005年 | 176篇 |
2004年 | 236篇 |
2003年 | 204篇 |
2002年 | 258篇 |
2001年 | 148篇 |
2000年 | 149篇 |
1999年 | 132篇 |
1998年 | 66篇 |
1997年 | 43篇 |
1996年 | 43篇 |
1995年 | 51篇 |
1994年 | 39篇 |
1993年 | 39篇 |
1992年 | 97篇 |
1991年 | 96篇 |
1990年 | 81篇 |
1989年 | 81篇 |
1988年 | 88篇 |
1987年 | 75篇 |
1986年 | 65篇 |
1985年 | 67篇 |
1984年 | 47篇 |
1983年 | 43篇 |
1982年 | 37篇 |
1981年 | 36篇 |
1980年 | 49篇 |
1979年 | 52篇 |
1978年 | 41篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1974年 | 73篇 |
1973年 | 40篇 |
1972年 | 48篇 |
1971年 | 65篇 |
1970年 | 80篇 |
1969年 | 101篇 |
1968年 | 102篇 |
1967年 | 119篇 |
1966年 | 125篇 |
排序方式: 共有5430条查询结果,搜索用时 15 毫秒
31.
Ludman E Katon W Bush T Rutter C Lin E Simon G Von Korff M Walker E 《Psychological medicine》2003,33(6):1061-1070
BACKGROUND: A randomized trial of a primary care-based intervention to prevent depression relapse resulted in improved adherence to long-term antidepressant medication and depression outcomes. We evaluated the effects of this intervention on behavioural processes and identified process predictors of improved depressive symptoms. METHOD: Patients at high risk for depression recurrence or relapse following successful acute phase treatment (N=386) were randomly assigned to receive a low intensity 12-month intervention or continued usual care. The intervention combined education about depression, shared decision-making regarding use of maintenance pharmacotherapy and cognitive-behavioural strategies to promote self-management. Baseline, 3, 6, 9 and 12-month interviews assessed patients' self-care practices, self-efficacy for managing depression and depressive symptoms. RESULTS: Intervention patients had significantly greater self-efficacy for managing depression (P<0.01) and were more likely to keep track of depressive symptoms (P<0.0001), monitor early warning signs (P<0.0001), and plan for coping with high risk situations (P<0.0001) at all time points compared to usual care control patients. Self-efficacy for managing depression (P<0.0001), keeping track of depressive symptoms (P=0.05), monitoring for early warning signs (P=0.01), engaging in pleasant activities (P<0.0001) and engaging in social activities (P<0.0001) positively predicted improvements in depression symptom scores. CONCLUSIONS: A brief intervention designed to target cognitive-behavioural factors and promote adherence to pharmacotherapy in order to prevent depression relapse was highly successful in changing several behaviours related to controlling depression. Improvements in self-efficacy and several self-management behaviours that were targets of the intervention were significantly related to improvements in depression outcome. 相似文献
32.
33.
A 50-kDa membrane protein mediates sialic acid-independent binding and infection of conjunctival cells by adenovirus type 37 总被引:6,自引:0,他引:6
The ocular tropism of adenovirus type 37 (Ad37) does not correlate with the wide distribution of the 46-kDa coxsackievirus and adenovirus receptor (CAR), the major receptor for most adenovirus serotypes. We previously found that Ad37 infects and binds well to conjunctival cells (Chang C), but poorly to lung epithelial (A549) cells that express CAR and hypothesized that this serotype uses a distinct receptor that is selectively expressed on conjunctival cells. To test this, we produced particles of a fiber-deleted Ad5 vector containing the Ad37 fiber protein. The "pseudotyped" vector infected Chang C cells better than A549 cells using a CAR-independent pathway. Ad37 binding was calcium-dependent and was abolished by protease digestion of cell surface proteins. Using a virus overlay protein blot assay (VOPBA), we detected calcium-dependent Ad37 binding to 50- and 60-kDa membrane proteins on permissive Chang C cells. In contrast, calcium-dependent binding was detected with only the 60-kDa protein on nonpermissive A549 cells. Ad19p, a closely related serotype that failed to bind to conjunctival cells, recognized the 60-kDa, but not the 50-kDa, protein. Ad37 has been reported to use sialic acid instead of CAR as a cell receptor on A549 cells. Pretreatment of Chang C cells with neuraminidase abolished Ad37 binding to only the 60-kDa protein, suggesting that sialic acid mediates Ad37 binding to the 60-kDa protein. The pseudotyped Ad37 vector was also able to infect neuraminidase-treated Chang C cells. Thus, subgroup D adenoviral binding to the 50-kDa protein is calcium-dependent and cell type- and serotype-specific, whereas binding to the 60-kDa protein is not necessary for infection of conjunctival cells. Together, these data suggest that the 50-kDa protein is the major receptor for Ad37 on conjunctival cells. 相似文献
34.
Propamidine, one of the diamidines used against infections with babesiae has inhibitory and enhancing effects on complement activation as assessed by immune haemolysis of sensitized sheep red cells. Utilization of C1 is powerfully, that of C3 weakly improved by propamidine while activation and/or fixation of C4, C5 and to a lesser degree of C8 and C9 are inhibited. At low concentrations of propamidine (less than 2 mM) the enhancing effects, at higher concentrations the inhibitory effects predominate. Inhibition is produced, in some cases certainly, in others likely, by interference of propamidine with binding properties of complement components. None of the complement enzymes, C1s, C42 or C3bBb was inhibited in its hydrolytic activity. The possible significance of propamidine actions is discussed. 相似文献
35.
Christian Ertel Neil S. Millar Peter T. Emmerson Volker Schirrmacher Paul Von Hoegen 《European journal of immunology》1993,23(10):2592-2596
In attempt to increase the induction of peptide-specific cytolytic T cells (CTL) we investigated the effect of the Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) gene product on the activation of peptide-specific CTL. Spleen cells of CH3 mice immunized against the influenza nucleoprotein peptide 50–63 (NP 50–63) were restimulated in vitro (i) with peptide-pulsed syngeneic fibroblast cells (Ltk?) as antigen-presenting cells, which were in addition (ii) infected with NDV or (iii) stably transfected with the HN cDN A of NDV. A greater than sixfold increase in peptide-specific CTL responses was observed in cultures restimulated with peptide-pulsed Ltk? cells which co-expressed viral hemagglutinin due to either infection or transfection. A similar augmentation was seen in CTL responses against other types of antigen (major histocompatibility complex alloantigens, minor histocompatibility antigens or tumor antigens) when suboptimal cultures were stimulated with the respective antigen-presenting cells modified by NDV infection. These findings suggest that NDV or viral HN expressed on antigen-presenting cells or tumor cells can exert a T cell co-stimulatory function. 相似文献
36.
37.
Distinguishing characteristics of a new neuroblastoma cell line 总被引:3,自引:0,他引:3
J T Casper J M Trent J Harb V Piaskowski M Helmsworth J Finlan D D Von Hoff 《Cancer Genetics and Cytogenetics》1983,10(2):177-186
The characteristics of a new neuroblastoma cell line (MC-NB-1) established from the bone marrow of a 2-year-old male are described. Morphologically, the cells appear as flattened and epithelial-like or as small and spherical. Electron microscopy demonstrated microtubules and dense core secretory granules. The doubling time was approximately 35 hr. Isoenzyme patterns and catecholamine secretion indicated a human line of neuronal origin. The soft agar tumor colony forming system demonstrated drug resistance in vitro comparable to in vivo nonresponsiveness. The stemline karyotype of MC-NB-1 is 44,Y,del(1) (p22:), -4, -7, +del(7)(q22:), -16, +t(7;16)(16pter leads to 16q24::7q22 leads to 7q32), -17. Additionally, double-minute bodies were observed. However, no evidence of homogeneous staining regions (HSRs) were detected. 相似文献
38.
Nonspecific phosphatases of rabbit endometrial carcinoma 总被引:1,自引:0,他引:1
39.
Kopp MV Brauburger J Riedinger F Beischer D Ihorst G Kamin W Zielen S Bez Friedrichs F Von Berg A Gerhold K Hamelmann E Hultsch Kuehr J 《The Journal of allergy and clinical immunology》2002,110(5):728-735
BACKGROUND: Binding of allergens with IgE to the IgE receptors on mast cells and basophils results in the release of inflammatory mediators as sulfidoleukotrienes (SLTs), triggering allergic cascades that result in allergic symptoms, such as asthma and rhinitis. OBJECTIVE: We sought to investigate whether anti-IgE (Oma-lizumab), a humanized monoclonal anti-IgE antibody, in addition to specific immunotherapy (SIT) affects the leukotriene pathway. METHODS: Ninety-two children (age range, 6-17 years) with sensitization to birch and grass pollens and with seasonal allergic rhinitis were included in a phase III, placebo- controlled, multicenter clinical study. All subjects were randomized to one of 4 treatment groups. Two groups subcutaneously received birch SIT and 2 groups received grass SIT for at least 14 weeks before the start of the birch pollen season. After 12 weeks of SIT titration, placebo or anti-IgE was added for 24 weeks. The primary clinical efficacy variable was symptom load (ie, the sum of daily symptom severity score and rescue medication score during pollen season). Blood samples taken at baseline and at the end of study treatment after the grass pollen season were used for separation of leukocytes in this substudy. After in vitro stimulation of the blood cells with grass and birch pollen allergens, SLT release (LTC4, LTD4, and LTE4) was quantified by using the ELISA technique. RESULTS: Before the study treatment, SLT release to birch and grass pollen exposure did not differ significantly among the 4 groups. Under treatment with anti-IgE + SIT-grass (n = 23), a lower symptom load occurred during the pollen season compared to placebo + SIT-grass (n = 24, P =.012). The same applied to both groups receiving birch SIT (n = 23 and n = 22, respectively; P =.03). At the end of treatment, the combination of anti-IgE plus grass SIT, as well as anti-IgE plus birch SIT, resulted in significantly lower SLT release after stimulation with the corresponding allergen (416 ng/L [5th-95th percentile, 1-1168] and 207 ng/L [1-860 ng/L], respectively) compared with placebo plus SIT (2490 ng/L [384-6587 ng/L], P =.001; 2489 ng/L [1-5670 ng/L], P =.001). In addition, treatment with anti-IgE was also followed by significantly lower SLT releases to the allergens unrelated to SIT (grass SIT: 300 ng/L [1-2432 ng/L] in response to birch allergen; birch SIT: 1478 ng/L [1-4593 ng/L] in response to grass pollen) in comparison with placebo (grass SIT: 1850 ng/L [1-5499 ng/L], P =.001; birch SIT: 2792 ng/L [154-5839 ng/L], P =.04]. CONCLUSION: Anti-IgE therapy reduces leukotriene release of peripheral leukocytes stimulated with allergen in children with allergic rhinitis undergoing allergen immunotherapy independent of the type of SIT allergen used. 相似文献
40.
Condensation of benzamidine hydrochloride with acetanhydride gives 2-methyl-4.6-diphenyl-s-triazine with yields of more than 90%. The corresponding reaction of terephthaldiamidine dihydrochloride leads to poly[(6-methyl-2.4-s-triazinediyl)-1.4-phenylene] of low degree of polymerization, soluble in conc. sulfuric acid. Benzamidine-N-carboxylic acid ethylester is converted to 2-hydroxy-4.6-diphenyl-s-triazine in a yield of 99% by heating. Terephthaldiamidine-di-N-carboxylic acid ethylester decomposes by heat treatment under loss of ethyl carbamate to the insoluble white poly[(6-hydroxy-2.4-s-triazinediyl)-1.4-phenylene]. 相似文献