全文获取类型
收费全文 | 9055篇 |
免费 | 544篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 206篇 |
妇产科学 | 249篇 |
基础医学 | 1257篇 |
口腔科学 | 195篇 |
临床医学 | 938篇 |
内科学 | 2175篇 |
皮肤病学 | 89篇 |
神经病学 | 760篇 |
特种医学 | 293篇 |
外科学 | 1110篇 |
综合类 | 110篇 |
一般理论 | 13篇 |
预防医学 | 704篇 |
眼科学 | 175篇 |
药学 | 692篇 |
中国医学 | 5篇 |
肿瘤学 | 580篇 |
出版年
2023年 | 45篇 |
2022年 | 66篇 |
2021年 | 164篇 |
2020年 | 135篇 |
2019年 | 155篇 |
2018年 | 171篇 |
2017年 | 136篇 |
2016年 | 115篇 |
2015年 | 209篇 |
2014年 | 259篇 |
2013年 | 420篇 |
2012年 | 650篇 |
2011年 | 668篇 |
2010年 | 346篇 |
2009年 | 306篇 |
2008年 | 572篇 |
2007年 | 644篇 |
2006年 | 625篇 |
2005年 | 597篇 |
2004年 | 574篇 |
2003年 | 518篇 |
2002年 | 560篇 |
2001年 | 84篇 |
2000年 | 83篇 |
1999年 | 113篇 |
1998年 | 111篇 |
1997年 | 97篇 |
1996年 | 85篇 |
1995年 | 90篇 |
1994年 | 68篇 |
1993年 | 64篇 |
1992年 | 66篇 |
1991年 | 79篇 |
1990年 | 57篇 |
1989年 | 49篇 |
1988年 | 44篇 |
1987年 | 42篇 |
1986年 | 48篇 |
1985年 | 37篇 |
1984年 | 47篇 |
1983年 | 31篇 |
1982年 | 60篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 32篇 |
1978年 | 33篇 |
1977年 | 42篇 |
1976年 | 17篇 |
1975年 | 25篇 |
1973年 | 25篇 |
排序方式: 共有9639条查询结果,搜索用时 62 毫秒
81.
Jonathan D Darer Wenke Hwang Hoangmai H Pham Eric B Bass Gerard Anderson 《Academic medicine》2004,79(6):541-548
PURPOSE: Although more than 125 million North Americans have one or more chronic conditions, medical training may not adequately prepare physicians to care for them. The authors evaluated physicians' perceptions of the adequacy of their chronic illness care training to and the effects of training on their attitudes toward care of persons with chronic conditions. METHOD: In November 2000 through June 2001, the authors surveyed by telephone a random sample of U.S. physicians who had > or =20 hours of patient contact per week. The interview instrument examined demographics, career satisfaction, practice characteristics, perceived adequacy of chronic illness care training in ten competencies (geriatric syndromes, chronic pain, nutrition, developmental milestones, end-of-life care, psychosocial issues, patient education, assessment of caregiver needs, coordination of services, and interdisciplinary teamwork), and effect of training on attitudes toward chronic illness care. RESULTS: Of 1,905 eligible physicians, 1,236 (65%) responded (270 family or general practitioners, 231 internists, 129 pediatricians, 335 nonsurgical specialists, and 271 surgeons). Most physicians reported their chronic disease training was less than adequate for all ten competencies. Family practitioners were more likely (p <.05) to report adequate training in seven competencies compared with internists, and in two to four competencies when compared with pediatricians, nonsurgical specialists, or surgeons. Most physicians reported that training had a positive effect on attitudes toward care of people with chronic conditions, including the ability to make a difference in their lives (74-84%). CONCLUSIONS: Physicians perceived their medical training for chronic illness care was inadequate. Medical schools and residencies may need to modify curricula to better prepare physicians to treat the growing number of people with chronic conditions. 相似文献
82.
Allergen immunotherapy induces a suppressive memory response mediated by IL-10 in a mouse asthma model 总被引:2,自引:0,他引:2
Vissers JL van Esch BC Hofman GA Kapsenberg ML Weller FR van Oosterhout AJ 《The Journal of allergy and clinical immunology》2004,113(6):235-1210
BACKGROUND: Human studies have demonstrated that allergen immunotherapy induces memory suppressive responses and IL-10 production by allergen-specific T cells. Previously, we established a mouse model in which allergen immunotherapy was effective in the suppression of allergen-induced asthma manifestations. OBJECTIVE: In this study, we examined whether immunotherapy induces a long-lasting effect and investigated the role of IL-10 in successful immunotherapy. METHODS: Ovalbumin-sensitized BALB/c mice were treated with 3 injections of ovalbumin (1 mg, subcutaneous) on alternate days. After a short interval (1 week) and after a long interval (5 weeks), mice were challenged by ovalbumin inhalation, and subsequently, airway reactivity, airway eosinophilia, ovalbumin-specific IgE, and T(H)2 cytokine profile were measured. Flow cytometry and blocking of IL-10 receptors in vivo were used to gain insight in the role of IL-10 in the beneficial effects of allergen immunotherapy. RESULTS: After a long interval between ovalbumin immunotherapy and ovalbumin challenge, the development of airway eosinophilia and hyperresponsiveness to methacholine were as strongly suppressed as after a short interval. These suppressive effects coincided with significantly reduced serum ovalbumin-specific IgE levels and T(H)2 cytokine production. On immunotherapy, the IL-5:IL-10 ratio in the bronchoalveolar lavage fluid shifted toward IL-10. In ovalbumin-restimulated lung cell and thoracic lymph node cultures from these mice, IL-5 levels dramatically decreased, whereas the percentage of IL-10(+)CD4(+) T cells was not affected. Finally, in mice treated with mAb against IL-10 receptors, the beneficial effects of immunotherapy were largely abrogated. CONCLUSION: These data demonstrate that allergen immunotherapy induces a memory suppressive effect in which IL-10 is essential. 相似文献
83.
Induced recruitment of NK cells to lymph nodes provides IFN-gamma for T(H)1 priming 总被引:13,自引:0,他引:13
Martín-Fontecha A Thomsen LL Brett S Gerard C Lipp M Lanzavecchia A Sallusto F 《Nature immunology》2004,5(12):1260-1265
Naive T cells are stimulated by antigen-presenting dendritic cells (DCs) in secondary lymphoid organs, but whether other types of cell participate in T cell priming is unclear. Here we show in mice that natural killer (NK) cells, which are normally excluded from lymph nodes, are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs. Recruitment of NK cells is also induced by some, but not all, adjuvants and correlates with the induction of T helper cell type 1 (T(H)1) responses. NK cell depletion and reconstitution experiments show that NK cells provide an early source of interferon-gamma (IFN-gamma) that is necessary for T(H)1 polarization. Taken together, our results identify an induced pathway of NK cell migration in antigen-stimulated lymph nodes and a mechanism by which some adjuvants may facilitate T(H)1 responses. 相似文献
84.
High risk pregnancies in hypopituitary women 总被引:1,自引:0,他引:1
Overton CE Davis CJ West C Davies MC Conway GS 《Human reproduction (Oxford, England)》2002,17(6):1464-1467
BACKGROUND: Various short papers have suggested that pregnancies in women with hypopituitarism are high risk but no formal assessment of pregnancy outcome has yet been reported. METHODS: An audit was carried out concerning the outcome of 18 pregnancies in nine women who underwent ovulation induction in a single centre over 20 years. RESULTS: The live birth rate was 61%, miscarriage rate 28% and mid-trimester uterine death rate 11% with no survivors from four sets of twins. The Caesarian section rate was 100% and half of the live births were on or below the 10th centile for weight. One woman successfully breast-fed. CONCLUSIONS: Women with hypopituitarism have high-risk pregnancies, perhaps because of a uterine defect secondary to endocrine deficiency. Fertility treatment must strive for singleton pregnancies with application of particularly strict criteria to avoid twin pregnancies. Early elective Caesarian section is probably warranted in this group. 相似文献
85.
David Laurin Eric Spierings Lars T van der Veken Abdelbasset Hamrouni J H Frederik Falkenburg Gerard Souillet Corine Vermeulen Annie Farre Claire Galambrun Dominique Rigal Yves Bertrand Els Goulmy Assia Eljaafari 《Biology of blood and marrow transplantation》2006,12(11):1114-1124
In vitro stimulation of human female T cells with male HLA-identical dendritic cells resulted in the generation of HLA-DQB1*0501/0502-restricted minor histocompatibility H-Y antigen-specific CD4(+) T cell clones. Two clones generated from different HLA-identical pairs were analyzed. Use of HLA-DQ5-expressing female Epstein-Barr virus transformed B lymphoblastoid cell lines transfected with various H-Y genes and loaded with overlapping peptides demonstrated that both T cell clones are specific for a peptide encoded by DDX3Y. Previously, an HLA-DQ5-restricted T cell clone specific for the same peptide was isolated from a patient with graft-versus-host disease. Thus, we compared the T cell receptor (TCR) rearrangements of the 2 in vitro generated T cell clones and the ex vivo isolated T cell clone. All 3 clones shared the same TCRBV5-4* gene segment and 2 of 3 clones also used similar TCR-Valpha segments. Our results suggest that T cells recognizing the HLA-DQ5/DDX3Y T cell epitope might be characterized by a relatively limited TCR-beta repertoire. The differences in the junctional TCR-beta region had no effect on the antigen specificity, but altered the capacity of the TCR to distinguish the HLA-DQ5/DDX3Y complex from its allelic counterpart. The results also demonstrate that in vitro stimulation of T cells with allogeneic HLA-identical dendritic cells may facilitate the characterization of in vivo, potentially relevant HLA class II-restricted minor H epitopes. 相似文献
86.
Detection of Staphylococcal Superantigenic Toxins by a CD69-Specific Cytofluorimetric Assay Measuring T-Cell Activation 总被引:3,自引:1,他引:3 下载免费PDF全文
Gerard Lina Grgoire Cozon Josette Ferrandiz Timothy Greenland Franois Vandenesch Jerome Etienne 《Journal of clinical microbiology》1998,36(4):1042-1045
The presence of staphylococcal superantigenic toxins in the supernatants of liquid cultures was detected by an easy and rapid method assessing the activation of T lymphocytes by cytofluorimetric measurement of CD69 expression. Staphylococcus aureus cells were grown in Eagle’s minimum essential medium supplemented with 5% heat-inactivated fetal calf serum. Supernatant fluids from all S. aureus strains producing superantigen-related toxins, including enterotoxins A to E, toxic shock syndrome toxin, and exfoliative toxins A and B, induced CD69 expression in a significantly higher number of T cells than a cutoff of 2%. This CD69 assay might be used for initial detection of superantigens from S. aureus strains isolated in the context of staphylococcal toxemia or related chronic human diseases such as atopic dermatitis or Kawasaki syndrome. 相似文献
87.
The potential for a bioterrorism-induced smallpox outbreak has been much discussed of late. The literature of the late 1960s stressed that the distinction between smallpox and the other viral-induced vesicle-forming diseases, namely varicella zoster and disseminated herpes simplex, was difficult to make. Given that the cutaneous manifestations of smallpox would be among the initial symptoms, we reviewed 2 cases of smallpox diagnosed in South America in the 1970s in conjunction with 9 cases of multiple skin vesicles diagnosed as either disseminated herpes simplex or varicella-zoster. These were examined by routine hematoxylin and eosin stain (H&E) as well as by in situ hybridization. A blind review of the cases demonstrated that each showed striking intraepithelial vesicles containing multinucleated squamous cells exhibiting a ground glass appearance of the nuclear chromatin. Thus, as expected, routine H&E examination could not differentiate the 2 smallpox cases from the other 9 samples. In situ hybridization easily distinguished the 2 cases of smallpox from the other 9 samples, 5 of which contained varicella-zoster (two had been misdiagnosed as herpes) and the other 4 were disseminated herpes simplex. The in situ test, readily accomplished in any histology-based molecular laboratory in 4 hours, allows for the rapid and specific identification of smallpox infection and, importantly, its distinction from its mimics. Formalin fixation, which is optimal for in situ hybridization, guarantees the inactivation of the smallpox virus. 相似文献
88.
Velthuis JH de Bont HJ Medema JP Kuppen PJ Mulder GJ Nagelkerke JF 《Immunobiology》2003,207(2):115-127
Natural Killer (NK) cells can induce apoptosis in target cells in at least four ways: by secretion of granzyme B/perforin (GrB/P) and via the CD95L, TRAIL and TNF-α pathways. In this study we examined the pathways used by interleukin-2 activated rat NK (A-NK) cells to induce apoptosis in the rat colon carcinoma cell line CC531s. Co-incubation of A-NK cells with CC531s cells for three hours resulted in 70% apoptosis in the latter. Addition of the GrB/P pathway-inhibitor concanamycin A reduced the number of apoptotic cells to 54%. Blockade of the CD95L, TRAIL and TNF-α pathways by specific antibodies hardly had an additional effect. However, co-incubation with transfected MEC cells that expressed CD95L or 2PK3-cells that expressed TRAIL did induce apoptosis in CC531s cells. Furthermore the A-NK cells contained CD95L and TRAIL. However, comparison of non- and permeabilized cells revealed that the majority of TRAIL was present in the cytosol of A-NK cells and was not available for induction of apoptosis. The presence of elevated levels of bcl-2 in CC531 cells reduced the sensitivity towards induction of apoptosis both by A-NK cells as well as the CD95L and TRAIL expressing cell lines. Using the caspase-inhibitors ac-IEPD-CHO, ac-DEVD-CHO and zVAD-fmk, it was shown that inhibition of the effector caspase-3 prevented A-NK cell induced apoptosis in CC531-bcl-2 cells, but not in CC531s cells. In conclusion, A-NK cells kill by secretion of GrB/P and not by the CD95L, TRAIL or TNF pathways albeit both CD95L and TRAIL are produced by the A-NK cells. 相似文献
89.
Nijhuis-van der Sanden MW Smits-Engelsman BC Eling PA Nijhuis BJ Van Galen GP 《Developmental neuropsychology》2002,22(3):643-670
The article aims to discriminate between 2 features that in principle both may be characteristic of the frequently observed poor motor performance in girls with Turner's syndrome (TS). On the one hand, a reduced movement speed that is independent of variations in spatial accuracy demands and therefore suggests a problem in motor execution. On the other hand, a disproportional slowing down of movement speed under spatial-accuracy demands, indicating a more central problem in motor programming. To assess their motor performance problems, 15 girls with TS (age 9.6-13.0 years) and 14 female controls (age 9.1-13.0 years) were tested using the Movement Assessment Battery for Children (MABC). In additionally, an experimental procedure using a variant of Fitts' graphic aiming task was used to try and disentangle the role of spatial-accuracy demands in different motor task conditions. The results of the MABC reestablish that overall motor performance in girls with TS is poor. The data from the Fitts' task reveal that TS girls move with the same accuracy as their normal peers but show a significantly lower speed independent of task difficulty. We conclude that a problem in motor execution is the main factor determining performance differences between girls with TS and controls. 相似文献
90.
Michiel W. P. Bleeker Miriam Kooijman Gerard A. Rongen Maria T. E. Hopman Paul Smits 《The Journal of physiology》2005,565(2):685-694
Deconditioning is a risk factor for cardiovascular disease. Exercise reduces this risk, possibly by improving the vascular endothelial nitric oxide (NO) pathway. The effect of deconditioning on the NO pathway is largely unknown. This study was designed to assess baseline NO availability in the leg vascular bed after extreme, long-term deconditioning (spinal cord-injured individuals, SCI) as well as after moderate, short-term deconditioning (4 weeks of unilateral lower limb suspension, ULLS). For this purpose, seven SCI were compared with seven matched controls. Additionally, seven healthy subjects were studied pre- and post-ULLS. Leg blood flow was measured by venous occlusion plethysmography at baseline and during infusion of 5 incremental dosages of N G -monomethyl- l -arginine ( l -NMMA) into the femoral artery. Sodium nitroprusside (SNP) was infused to test vascular responsiveness to NO. Baseline leg vascular resistance tended to be higher in SCI compared with controls (37 ± 4 versus 31 ± 2 arbitrary units (AU), P = 0.06). Deconditioning altered neither the vasoconstrictor response to l -NMMA (increase in resistance in SCI versus controls: 102 ± 33% versus 69 ± 9%; pre- versus post-ULLS: 95 ± 18% versus 119 ± 15%), nor the vascular responsiveness to NO. In conclusion, two human in vivo models of deconditioning show a preserved baseline NO availability in the leg skeletal muscle vascular bed. 相似文献