全文获取类型
收费全文 | 12142篇 |
免费 | 958篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 290篇 |
妇产科学 | 180篇 |
基础医学 | 1634篇 |
口腔科学 | 246篇 |
临床医学 | 1200篇 |
内科学 | 2784篇 |
皮肤病学 | 131篇 |
神经病学 | 1053篇 |
特种医学 | 383篇 |
外科学 | 2006篇 |
综合类 | 175篇 |
一般理论 | 10篇 |
预防医学 | 948篇 |
眼科学 | 496篇 |
药学 | 754篇 |
中国医学 | 45篇 |
肿瘤学 | 743篇 |
出版年
2022年 | 63篇 |
2021年 | 179篇 |
2020年 | 100篇 |
2019年 | 177篇 |
2018年 | 185篇 |
2017年 | 128篇 |
2016年 | 147篇 |
2015年 | 185篇 |
2014年 | 290篇 |
2013年 | 521篇 |
2012年 | 707篇 |
2011年 | 785篇 |
2010年 | 421篇 |
2009年 | 418篇 |
2008年 | 648篇 |
2007年 | 737篇 |
2006年 | 727篇 |
2005年 | 756篇 |
2004年 | 703篇 |
2003年 | 718篇 |
2002年 | 719篇 |
2001年 | 98篇 |
2000年 | 88篇 |
1999年 | 118篇 |
1998年 | 169篇 |
1997年 | 139篇 |
1996年 | 129篇 |
1995年 | 112篇 |
1994年 | 104篇 |
1993年 | 97篇 |
1992年 | 97篇 |
1991年 | 73篇 |
1990年 | 60篇 |
1989年 | 64篇 |
1988年 | 53篇 |
1987年 | 56篇 |
1985年 | 64篇 |
1984年 | 86篇 |
1983年 | 87篇 |
1982年 | 126篇 |
1981年 | 118篇 |
1980年 | 92篇 |
1979年 | 61篇 |
1978年 | 78篇 |
1977年 | 81篇 |
1976年 | 64篇 |
1975年 | 70篇 |
1974年 | 66篇 |
1973年 | 60篇 |
1964年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 547 毫秒
61.
Ireen M. Proot Harry F. J. M. Crebolder Huda Huijer Abu-Saad Ruud H. J. Ter Meulen 《Scandinavian journal of caring sciences》1998,12(3):139-145
This article presents a concept analysis of autonomy in relation to the rehabilitation of stroke patients. Analysis of the results of a literature survey provided three important concepts of autonomy in the field of biomedical ethics: self-governance, self-realization and actual autonomy. These concepts are compared with concepts from caring sciences and summarized in a table. The results indicate the importance of the social environment (formal and informal caregivers) for the restoration of autonomy. Because of the patient's condition and context, a social concept of autonomy makes more sense in the rehabilitation of stroke patients in nursing homes than does an individual concept. The concept analysis sheds light on the fact that the majority of studies regarding patient autonomy are primarily based on theoretical reflections, not on empirical studies. More research is warranted to gather information on how patients themselves consider and appreciate autonomy during rehabilitation, to explore the views of stroke patients' formal and informal caregivers and to investigate whether a social concept of autonomy is suitable for all phases of rehabilitation. Concerning the practice of rehabilitation, no definite conclusion can be given as yet. 相似文献
62.
63.
Immunochemical characterization of cytochrome P-450 isozymes responsible for benzene oxidation in the rat liver 总被引:4,自引:0,他引:4
Nakajima Tamie; Elovaara Eivor; Park Sang S.; Gelboin Harry V.; Hietanen Eino; Vainio Hani 《Carcinogenesis》1989,10(9):1713-1717
The contribution of cytochrome P-450 isozymes to benzene metabolismin liver microsomes from fed, fasted, pyrazole-, pbenobarbital(PB)- and ethanol-treated rats and in respective isocaloriccontrols was investigated using monoclonal antibodies (mAbs).Clone 1-7-1 mAb did not inhibit benzene metabolism, whereasclone 2-66-3 inhibited only in PB-induced microsomes at a highconcentration of benzene (6.26 mM), and clone 1-91-3 mAb inhibitedbenzene metabolism in all cases. The degree of inhibition wasas follows: fed isocaloric control PB < fasted < pyrazole ethanol. The pattern of inhibition was similar with clone 1-91-3for low (0.23 mM) and high concentrations of benzene, exceptin PB-induced mkrosomes. Western blot analysis showed that clone1-7-1 mAb did not bind any liver mkrosomal protein in the regionof cytochrome P-450s, whereas with clone 2-66-3 a clear-cutband was seen only in liver microsomes from PB-treated rats,with clone 1-98-1, a band was detected in mkrosomes from alltreated groups, in the following order: PB = isocaloric control< fed < fasted < pyrazole < ethanol. These resultsindicate that (i) cytochromes P-450b,e and P-450J contributeto benzene metabolism in rat liver; (ii) the former has a lowaffinity to benzene and is induced by PB; and (iii) P-450J hasa high affinity to benzene and is induced by 1-day fasting,pyrazole and ethanol, but decreased by PB treatment. 相似文献
64.
Rojas OL González AM González R Pérez-Schael I Greenberg HB Franco MA Angel J 《Virology》2003,314(2):671-679
Using an intracellular cytokine assay, we recently showed that the frequencies of rotavirus (RV)-specific CD4(+) and CD8(+) T cells secreting INFgamma, circulating in RV infected and healthy adults, are very low compared to the frequencies of circulating cytomegalovirus (CMV) reactive T cells in comparable individuals. In children with acute RV infection, these T cells were barely or not detectable. In the present study, an ELISPOT assay enabled detection of circulating RV-specific INFgamma-secreting cells in children with RV diarrhea but not in children with non-RV diarrhea without evidence of a previous RV infection. Using microbead-enriched CD4(+) and CD8(+) T cell subsets, IFNgamma-secreting RV-specific CD8(+) but not CD4(+) T cells were detected in recently infected children. Using the same approach, both CD4(+) and CD8(+) RV-specific T cells were detected in healthy adults. Furthermore, stimulation of purified subsets of PBMC that express lymphocyte homing receptors demonstrated that RV-specific INFgamma-secreting CD4(+) T cells from adult volunteers preferentially express the intestinal homing receptor alpha4beta7, but not the peripheral lymph node homing receptor L-selectin. In contrast, CMV-specific INFgamma-secreting CD4(+) T cells preferentially express L-selectin but not alpha4beta7. These results suggest that the expression of homing receptors on virus-specific T cells depends on the organ where these cells were originally stimulated and that their capacity to secrete INFgamma is independent of the expression of these homing receptors. 相似文献
65.
66.
67.
Bank I Tick LW Hutten BA Kramer MH Middeldorp S Büller HR 《Pathophysiology of haemostasis and thrombosis》2003,33(4):192-196
Acquired and inherited thrombophilic factors increase the risk for (recurrent) venous thrombotic disease. However, little is known about the pathophysiological mechanisms causing these recurrences, or the persistence of thrombosis despite adequate treatment. Because residual thrombosis has been associated with a worse prognostic outcome, we performed an explorative study in order to investigate the prevalence of residual thrombotic lesions after anticoagulant treatment in patients with deep venous thrombosis. Thrombotic parameters as assessed by ultrasonography after a 12-week course of anticoagulants were used. Both thrombophilia in general and acquired thrombophilia in particular were found to be associated with the extent of residual thrombosis. Of the individual thrombophilic factors, protein C deficiency, prothrombin 20210A mutation, active malignant disease and lupus anticoagulant were associated with an increased risk of residual thrombotic mass. Patients with inherited thrombophilia did not differ from patients without any thrombophilic abnormality with regard to residual thrombotic mass [relative risk (RR) 1.3, 95% confidence interval (CI) 0.9-1.8], while acquired thrombophilic disorders increased the risk for residual thrombotic mass as compared to patients without any defect (RR 1.7, 95% CI 1.2-2.2). Although these results should be confirmed in a larger study, they might help us form hypotheses concerning why patients with thrombophilia are more prone to recurrent venous thromboembolic disease. 相似文献
68.
69.
OBJECTIVES: The purposes of this study were to examine possible ethnic and sex differences in plasma ET-1 levels at rest and in response to acute stress and to examine relationships between ET-1 and vasoconstrictive-mediated BP reactivity to stress. METHODS: Two hundred twenty-two adolescents (mean age = 18.5 +/- 2.8 years; 130 [70 males] EAs and 92 [48 males] AAs) completed two stressors (video game, forehead cold). Hemodynamic measures and blood samples were collected at catheter insertion and before and immediately after the two stressors, separated by 20-minute rest periods. RESULTS: AAs and males exhibited higher levels of SBP and DBP and of TPRI and ET-1 at each sampling point compared with EAs and females, respectively (p values <.001). AAs and males exhibited greater increases in SBP, TPRI, and ET-1 in response to each stressor (p values <.05). Intraindividual correlations between ET-1 and hemodynamic parameters revealed that most individuals exhibited a positive association between ET-1, BP, and TPRI. However, some individuals exhibited a negative association between ET-1 and the above-mentioned hemodynamics, suggesting a compensatory vasodilation mechanism. CONCLUSION: The findings demonstrate significant sex and ethnicity differences in stress-induced vasoconstrictive peptide release and support the hypothesis that these differences may be important in explaining the ethnicity and sex differences in the prevalence of cardiovascular disease. 相似文献
70.
Expression of the chemokine receptors CCR4, CCR5, and CXCR3 by human tissue-infiltrating lymphocytes. 总被引:17,自引:0,他引:17 下载免费PDF全文
Eric J Kunkel Judie Boisvert Kristine Murphy Mark A Vierra Mark C Genovese Andrew J Wardlaw Harry B Greenberg Martin R Hodge Lijun Wu Eugene C Butcher James J Campbell 《The American journal of pathology》2002,160(1):347-355
Differential expression of adhesion molecules and chemokine receptors has been useful for identification of peripheral blood memory lymphocyte subsets with distinct tissue and microenvironmental tropisms. Expression of CCR4 by circulating memory CD4(+) lymphocytes is associated with cutaneous and other systemic populations while expression of CCR9 is associated with a small intestine-homing subset. CCR5 and CXCR3 are also expressed by discrete memory CD4(+) populations in blood, as well as by tissue-infiltrating lymphocytes from a number of sites. To characterize the similarities and differences among tissue-infiltrating lymphocytes, and to shed light on the specialization of lymphocyte subsets that mediate inflammation and immune surveillance in particular tissues, we have examined the expression of CCR4, CXCR3, and CCR5 on CD4(+) lymphocytes directly isolated from a wide variety of normal and inflamed tissues. Extra-lymphoid tissues contained only memory lymphocytes, many of which were activated (CD69(+)). As predicted by classical studies, skin lymphocytes were enriched in CLA expression whereas intestinal lymphocytes were enriched in alpha(4)beta(7) expression. CCR4 was expressed at high levels by skin-infiltrating lymphocytes, at lower levels by lung and synovial fluid lymphocytes, but never by intestinal lymphocytes. Only the high CCR4 levels characteristic of skin lymphocytes were associated with robust chemotactic and adhesive responses to TARC, consistent with a selective role for CCR4 in skin lymphocyte homing. In contrast, CXCR3 and CCR5 were present on the majority of lymphocytes from each non-lymphoid tissue examined, suggesting that these receptors are unlikely to determine tissue specificity, but rather, may play a wider role in tissue inflammation. 相似文献