全文获取类型
收费全文 | 26223篇 |
免费 | 1749篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 213篇 |
儿科学 | 917篇 |
妇产科学 | 714篇 |
基础医学 | 3232篇 |
口腔科学 | 374篇 |
临床医学 | 4096篇 |
内科学 | 4804篇 |
皮肤病学 | 300篇 |
神经病学 | 2626篇 |
特种医学 | 532篇 |
外科学 | 2167篇 |
综合类 | 341篇 |
一般理论 | 65篇 |
预防医学 | 3752篇 |
眼科学 | 342篇 |
药学 | 1490篇 |
1篇 | |
中国医学 | 26篇 |
肿瘤学 | 2036篇 |
出版年
2023年 | 99篇 |
2022年 | 165篇 |
2021年 | 448篇 |
2020年 | 300篇 |
2019年 | 472篇 |
2018年 | 571篇 |
2017年 | 445篇 |
2016年 | 466篇 |
2015年 | 508篇 |
2014年 | 819篇 |
2013年 | 1279篇 |
2012年 | 1855篇 |
2011年 | 1927篇 |
2010年 | 1054篇 |
2009年 | 917篇 |
2008年 | 1778篇 |
2007年 | 1877篇 |
2006年 | 1862篇 |
2005年 | 1888篇 |
2004年 | 1817篇 |
2003年 | 1717篇 |
2002年 | 1592篇 |
2001年 | 210篇 |
2000年 | 160篇 |
1999年 | 263篇 |
1998年 | 347篇 |
1997年 | 255篇 |
1996年 | 245篇 |
1995年 | 231篇 |
1994年 | 198篇 |
1993年 | 188篇 |
1992年 | 140篇 |
1991年 | 121篇 |
1990年 | 106篇 |
1989年 | 108篇 |
1988年 | 104篇 |
1987年 | 99篇 |
1986年 | 92篇 |
1985年 | 89篇 |
1984年 | 127篇 |
1983年 | 118篇 |
1982年 | 140篇 |
1981年 | 123篇 |
1980年 | 117篇 |
1979年 | 62篇 |
1978年 | 74篇 |
1977年 | 69篇 |
1976年 | 55篇 |
1975年 | 46篇 |
1974年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Nancy K Ostrom 《Annals of allergy, asthma & immunology》2006,96(5):655-665
OBJECTIVES: To summarize the potential variables that contribute to the increased risk of asthma in women, outline therapeutic strategies that address these variables, and review current treatment recommendations for both pregnant and nonpregnant women with asthma. DATA SOURCES: Literature searches (MEDLINE and cross-references) were performed using the keywords asthma and women in combination with the terms compliance, depression, emergency department, hormones, menstruation, mortality, National Asthma Education and Prevention Program, osteoporosis, pregnancy, prevalence, smoking, and treatment. Searches were limited to human studies with data published before 2005. STUDY SELECTION: The author selected relevant articles for inclusion in this review. RESULTS: Fluctuations in sex hormones, menstruation, pregnancy, obesity, depression, medication nonadherence, and smoking may contribute to increased asthma symptoms or severity in women. Asthma control may be improved if physicians address conditions and behaviors associated with asthma variability and severity in women. Notably, asthma must be managed aggressively in pregnant women, because uncontrolled asthma can lead to perinatal complications. Asthma treatment in women is optimized through patient and physician adherence to national guideline recommendations, including provision of patient education and asthma action plans. CONCLUSIONS: Multiple variables throughout the female life cycle may influence asthma control. Successful asthma management requires an ongoing partnership between the patient and her physician to address physiologic (eg, sex hormones, pregnancy, obesity, depression) and nonphysiologic (eg, smoking, medication nonadherence) factors that may contribute to decreased asthma control. 相似文献
92.
Genome-wide linkage analysis of families with obsessive-compulsive disorder ascertained through pediatric probands 总被引:3,自引:0,他引:3
Hanna GL Veenstra-VanderWeele J Cox NJ Boehnke M Himle JA Curtis GC Leventhal BL Cook EH 《American journal of medical genetics》2002,114(5):541-552
The goal of this study was to identify chromosomal regions likely to contain susceptibility alleles for early-onset obsessive-compulsive disorder (OCD). A genome scan was done in 56 individuals from seven families ascertained through pediatric OCD probands; 27 of the 56 subjects had a lifetime diagnosis of definite OCD. Denser mapping of regions on chromosomes 2, 9, and 16 was subsequently done with those subjects and ten additional subjects from the largest family in the study. Direct interviews were completed with 65 of the 66 genotyped individuals. Relatives were interviewed blind to proband status. Of the 65 interviewed individuals, 32 had a lifetime diagnosis of definite OCD. Three of the seven probands had a history of Tourette disorder. Two of the 25 relatives with OCD had a tic history, whereas none of the 33 relatives without OCD had tics. The genome scan consisted of 349 microsatellite markers with an average between-marker distance of 11.3 centiMorgan (cM). Fine mapping was done with 24 additional markers at an average spacing of 1.6 cM. Parametric and nonparametric linkage analyses were conducted using GENEHUNTER(+). The maximum multipoint LOD score with a dominant model was 2.25 on 9p. However, with fine mapping and additional subjects, that LOD score decreased to 1.97. The maximum multipoint nonparametric LOD* score was 1.73 on 19q. The maximum multipoint LOD score with a recessive model was 1.40 on 6p. The results provide suggestive evidence for linkage on 9p and identify regions requiring further study with much larger samples. 相似文献
93.
The hypophysis of the brook trout is irrigated by blood vessels which originate from the internal carotid arteries. These are: (1) branches of the ventral hypothalamic arteries that give rise to an extensive capillary plexus in the neurohypophysis from which vessels extend into all regions of the adenohypophysis; (2) branches of the caudal hypothalamic artery that irrigate the saccus vasculosus and continue anteriorly to supply the ventral areas of the meta-adenohypophysis; (3) a caudal hypophyseal artery which vascularizes a portion of the meta-adenohypophysis however, this vessel is not always present; (4) a pair of small arteries which supply the peripheral regions of the gland directly from the carotids. Most of the neurosecretory fibers of the preoptic-hypophyseal tract terminate close to capillaries in the neurohypophysis. A few axons extend into meso-adenohypophyseal tissue. It is suggested that the secretory activities of the pro-, meso- and metaadenohypophyses are governed by hypothalamic factors that are chiefly transmitted to the gland cells via the vascular system (indirect control). However, the activity of the meso-adenohypophysis may also be regulated by factors which are transmitted directly to the cells from the endings of neurosecretory fibers which have traversed the neurohypophysis (direct control). The distribution and abundance of neurosecretion in the ventral hypophysis suggest the possibility of storage of hypothalamic products within this region. 相似文献
94.
Christianson SW Greiner DL Deluca D Leif J Phillips NE Hayes SM Hayashi S Joliat MJ Lyons BL Shultz LD 《Journal of autoimmunity》2002,18(2):119-130
Defects in the gene that encodes SHP-1 protein tyrosine phosphatase result in multiple hematopoietic abnormalities and generalized autoimmunity in viable motheaten (me(v)) mice. These mice also exhibit early thymic involution and abnormalities in T cell development. Here, we describe the use of fetal thymic organ culture (FTOC) and bone marrow adoptive transfer to study the effects of SHP-1 deficiency on thymocyte development. Chimeric FTOC established with normal bone marrow placed onto deoxyguanosine-treated fetal thymic lobes or onto scid fetal thymic lobes generated T cells. Bone marrow from SHP-1-deficient me(v)/ me(v) mice generated decreased numbers of T cells in chimeric FTOC established using deoxyguanosine-treated thymi but generated normal numbers in chimeric FTOC established using scid thymi. However, scid fetal thymi seeded with me(v)/ me(v) bone marrow also exhibited morphological abnormalities and contained elevated numbers of macrophages. Addition of IL-7 to me(v)/ me(v) bone marrow-seeded scid FTOC led to increased cell numbers, particularly of macrophages. Intrathymic injection of IL-7 partially restored the ability of progenitor cells in me(v)/ me(v) bone marrow to populate the thymus of adoptive recipients. We conclude that abnormal T cell development in me(v)/ me(v) mice may in part be due to defects in the ability of bone marrow-derived accessory cells to provide bioavailable IL-7 to developing thymocytes. 相似文献
95.
96.
Andrew Daly Steven McAfee Bimal Dey Christine Colby Leah Schulte Beow Yeap Robert Sackstein Nancy J Tarbell David Sachs Megan Sykes Thomas R Spitzer 《Biology of blood and marrow transplantation》2003,9(6):373-382
Infections are a common complication of allogeneic bone marrow transplantation and the leading cause of transplantation-related mortality. It had been hypothesized that transplantation following nonmyeloablative preparative regimens would result in fewer infections by causing less mucosal injury, less graft-versus-host disease, and allowing earlier immune reconstitution. We have retrospectively reviewed the infectious complications of 65 consecutive patients with advanced hematologic malignancies who underwent bone marrow transplantation using a novel preparative regimen consisting of cyclophosphamide, thymic irradiation, and in vivo T-cell depletion. Cytomegalovirus (CMV) infection occurred in 52% of cases in which the donor or recipient had evidence of prior CMV exposure. Using a strategy of preemptive therapy and secondary prophylaxis with ganciclovir, no CMV disease occurred. Infections with gram-positive bacteria predominated over the first 100 days after bone marrow transplantation. Thereafter, the relative proportion of gram-negative infections increased without a significant increase in episodes of neutropenia. The rate of bacterial infections was not influenced by relapse of the underlying malignancy. Seven patients developed infections with Aspergillus species, which was the most common infectious cause of death in these patients. Infections with viruses other than CMV (n=10) and with protozoan organisms (n=2) also occurred. The use of HLA-mismatched donors, the occurrence of grade II-IV acute graft-versus-host disease, and treatment with corticosteroids did not influence the risk of CMV or bacterial or fungal infections in patients who underwent transplantation following this preparative regimen. Overall, the incidence and spectrum of infections in this series was similar to the reported incidence of infections following conventional myeloablative allogeneic stem cell transplantation. We conclude that a quantitative T-cell deficiency in these extensively T-cell depleted patients may be a risk factor for infection, even in the absence of graft-versus-host disease. 相似文献
97.
98.
Repertoire of transcribed peripheral blood T-cell receptor beta chain variable-region genes in acute rheumatic fever. 下载免费PDF全文
W G Abbott M A Skinner L Voss D Lennon P L Tan J D Fraser I J Simpson R Ameratunga A Geursen 《Infection and immunity》1996,64(7):2842-2845
Patients with severe group A streptococcal infections have abnormalities in the Vbeta repertoire of peripheral blood T cells that are consistent with superantigen stimulation by cytoplasmic membrane proteins. The purpose of this study was to determine whether similar changes in Vbeta repertoire could be found for patients with acute rheumatic fever (ARF). The mean Vbeta repertoire of peripheral blood T cells in nine hospitalized ARF patients was similar to that of 34 controls and did not change during 6 months of follow-up in 6 of the ARF subjects. We were unable to detect changes in the Vbeta repertoire of peripheral blood T cells from patients with ARF that could be attributed to the influence of a superantigen. 相似文献
99.
Susceptible strains of mice that are naturally or experimentally infected with murine intestinal helicobacter species develop hepatic inflammatory lesions that have previously been described as chronic active hepatitis. The inflammatory infiltrates in some models of chronic autoimmunity or inflammation resemble tertiary lymphoid organs hypothesized to arise by a process termed lymphoid organ neogenesis. To determine whether hepatic inflammation caused by infection with helicobacter could give rise to tertiary lymphoid organs, we used fluorescence-activated cell sorting, immunohistochemistry, and in situ hybridization techniques to identify specific components characteristic of lymphoid organs in liver tissue sections and liver cell suspensions from helicobacter-infected mice. Small venules (high endothelial venules [HEVs]) in inflammatory lesions in Helicobacter species-infected livers were positive for peripheral node addressin. Mucosal addressin cell adhesion molecule also stained HEVs and cells with a staining pattern consistent with scattered stromal cells. The chemokines SLC (CCL 21) and BLC (CXCL13) were present, as were B220-positive B cells and T cells. The latter included a na?ve (CD45lo-CD62Lhi) population. These findings suggest that helicobacter-induced chronic active hepatitis arises through the process of lymphoid organ neogenesis. 相似文献
100.