全文获取类型
收费全文 | 10745篇 |
免费 | 728篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 123篇 |
儿科学 | 271篇 |
妇产科学 | 171篇 |
基础医学 | 1462篇 |
口腔科学 | 348篇 |
临床医学 | 1436篇 |
内科学 | 1824篇 |
皮肤病学 | 85篇 |
神经病学 | 957篇 |
特种医学 | 357篇 |
外科学 | 1092篇 |
综合类 | 160篇 |
一般理论 | 8篇 |
预防医学 | 1273篇 |
眼科学 | 309篇 |
药学 | 782篇 |
中国医学 | 11篇 |
肿瘤学 | 828篇 |
出版年
2023年 | 34篇 |
2022年 | 53篇 |
2021年 | 112篇 |
2020年 | 99篇 |
2019年 | 170篇 |
2018年 | 156篇 |
2017年 | 137篇 |
2016年 | 170篇 |
2015年 | 207篇 |
2014年 | 255篇 |
2013年 | 453篇 |
2012年 | 649篇 |
2011年 | 760篇 |
2010年 | 379篇 |
2009年 | 377篇 |
2008年 | 664篇 |
2007年 | 740篇 |
2006年 | 763篇 |
2005年 | 752篇 |
2004年 | 679篇 |
2003年 | 644篇 |
2002年 | 672篇 |
2001年 | 155篇 |
2000年 | 109篇 |
1999年 | 133篇 |
1998年 | 136篇 |
1997年 | 138篇 |
1996年 | 93篇 |
1995年 | 93篇 |
1994年 | 78篇 |
1993年 | 85篇 |
1992年 | 89篇 |
1991年 | 113篇 |
1990年 | 89篇 |
1989年 | 98篇 |
1988年 | 75篇 |
1987年 | 68篇 |
1986年 | 66篇 |
1985年 | 72篇 |
1984年 | 67篇 |
1983年 | 79篇 |
1982年 | 78篇 |
1981年 | 80篇 |
1980年 | 67篇 |
1979年 | 54篇 |
1978年 | 40篇 |
1977年 | 46篇 |
1976年 | 45篇 |
1974年 | 41篇 |
1972年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
Gillingham MB Connor WE Matern D Rinaldo P Burlingame T Meeuws K Harding CO 《Molecular genetics and metabolism》2003,79(2):114-123
Current dietary therapy for long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiency consists of fasting avoidance, and limiting long-chain fatty acid (LCFA) intake. This study reports the relationship of dietary intake and metabolic control as measured by plasma acylcarnitine and organic acid profiles in 10 children with LCHAD or TFP deficiency followed for 1 year. Subjects consumed an average of 11% of caloric intake as dietary LCFA, 11% as MCT, 12% as protein, and 66% as carbohydrate. Plasma levels of hydroxypalmitoleic acid, hydroxyoleic, and hydroxylinoleic carnitine esters positively correlated with total LCFA intake and negatively correlated with MCT intake suggesting that as dietary intake of LCFA decreases and MCT intake increases, there is a corresponding decrease in plasma hydroxyacylcarnitines. There was no correlation between plasma acylcarnitines and level of carnitine supplementation. Dietary intake of fat-soluble vitamins E and K was deficient. Dietary intake and plasma levels of essential fatty acids, linoleic and linolenic acid, were deficient. On this dietary regimen, the majority of subjects were healthy with no episodes of metabolic decompensation. Our data suggest that an LCHAD or TFP-deficient patient should adhere to a diet providing age-appropriate protein and limited LCFA intake (10% of total energy) while providing 10-20% of energy as MCT and a daily multi-vitamin and mineral (MVM) supplement that includes all of the fat-soluble vitamins. The diet should be supplemented with vegetable oils as part of the 10% total LCFA intake to provide essential fatty acids. 相似文献
63.
Raymond G. Goodwin Wenie S. Din Terri Davis-Smith Dirk M. Anderson Steven D. Gimpel Timothy A. Sato Charles R. Maliszewski Camilynn I. Brannan Neal G. Copeland Nancy A. Jenkins Terry Farrah Richard J. Armitage William C. Fanslow Craig A. Smith 《European journal of immunology》1993,23(10):2631-2641
4-1BB is an inducible T cell antigen that shows sequence homology to members of an emerging family of cytokine receptors, including those for tumor necrosis factor and nerve growth factor. To aid in the analysis of the function of 4-1BB we have utilized a soluble form of the molecule as a probe to identify and clone the gene which encodes its ligand. The ligand for 4-1BB is a type II membrane glycoprotein that has homology to tumor necrosis factor, lymphotoxin, and the ligands for CD40 and CD27, all of which are themselves ligands to receptors in this superfamily. The gene for 4-IBB is on mouse chromosome 4 and maps close to the p80 form of the tumor necrosis factor receptor as well as the gene for CD30. The gene for 4-IBB ligand maps to mouse chromosome 17, but considerably distal to the tumor necrosis factor and lymphotoxin genes. Interaction of 4-1BB with its ligand induces the proliferation of activated thymocytes and splenic T cells, a response which is mimicked on similar cell populations stimulated with an antibody to 4-1BB. 相似文献
64.
Terry L. Riss Masami Ogasawara Kenneth P. Karey David Danielpour Betty H. Stewart David A. Sirbasku 《Methods in Cell Science》1986,10(2):133-150
Summary Serum-free defined media have been developed for assay of the mitogenic effects of growth factors on human MCF-7, human T-47D, and mouse COMMA-D mammary cells as well as for identification of mitogens and inhibitors of GH4C1 rat pituitary tumor cell growth. These lines were shown to grow in vivo in response to a variety of hormones including estrogens and thyroid hormones. With mammary cells, complete hormonally and nutritionally defined media were established that supported continuous passage at 50 to 90% of the serum stimulated rate. The strategy used to measure mitogens for mammary cells was to identify nutritional conditions where the growth rate was reduced greatly without impairing the response to picomolar to nanomolar concentration of growth factors. The effects of polypeptide growth factors and tissue extracts were estimated by their addition to basal medium and measuring cell number increases or labeled thymidine incorporation into DNA. In a variation of this methodology, the MTW9/PL2 rat mammary cells were used to identify secreted autocrine growth factors; nutritionally defined conditions were sought for growth of these rat cells in the complete absence of exogenous growth factors. The factors secreted into the medium were detected by bioassays with COMMA-D or MCF-7 mammary cell lines. The effects of growth factors-inhibitors on pituitary cells were measured by a related method; the GH4C1 cells were grown at less than optimal rates in a defined medium designated TRM-1. Addition of mitogens to TRM-1 stimulated pituitary cell growth whereas addition of inhibitors caused reduced levels of growth. The methods described in this report offer new means of assaying growth factors-inhibitors for a range of mammary and pituitary tumor cells. 相似文献
65.
Interpersonal stressors and resources as predictors of parental adaptation following pediatric traumatic injury 总被引:4,自引:0,他引:4
Wade SL Stancin T Taylor HG Drotar D Yeates KO Minich NM 《Journal of consulting and clinical psychology》2004,72(5):776-784
The authors examined the relationship of preinjury interpersonal resources and stressors to parental adaptation following pediatric traumatic brain injury (TBI) and orthopedic injury. Parents of children with severe TBI (n = 53), moderate TBI (n = 56), and orthopedic injuries (n = 80) were assessed soon after injury, 6 and 12 months after the initial evaluation, and at an extended follow-up with a mean of 4 years postinjury. General linear model analyses provide support for both main and moderating effects of stressors and resources on parental adjustment. Support from friends and spouse was associated with less psychological distress, whereas family and spouse stressors were associated with greater distress. The results also reveal a marked decline in injury-related stress over follow-up for families in the severe TBI group who reported a combination of high stressors and high resources. The decline suggests that interpersonal resources attenuated long-term family burden because of severe TBI. The findings are discussed in terms of their implications for intervention following TBI. 相似文献
66.
Terry Reed Adolf Pfefferbaum Edith V. Sullivan Dorit Carmelli 《American journal of human biology》2002,14(3):338-346
MRI imaging was used to estimate volumes of corpus callosum structure in 45 pairs of identical (monozygotic, MZ) twins from the National Heart, Lung, and Blood Institute (NHLBI) twin study. Age range of the study subjects was from 68–78 years. Finger, palm, and footprint data (dermatoglyphics) collected at previous examinations of the NHLBI twin study were available for 39 pairs. The dermatoglyphics were scored for an index to retrospectively assess chorion type in MZ twin‐pairs. The results indicated an association between variability in various structures of the corpus callosum with some of these dermatoglyphic traits, suggesting greater structural variation within pairs with dichorionic placentas. In contrast, total intracranial volume, which has similar heritability estimates as a result of shared genetic effects with the corpus callosum, was unrelated to the dermatoglyphic traits. The results provide indirect evidence that the intrauterine environment may influence twin‐pair similarity of corpus callosum measures in adults. Am. J. Hum. Biol. 14:338–346, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
67.
Detection of Cattle Naturally Infected with Anaplasma marginale in a Region of Endemicity by Nested PCR and a Competitive Enzyme-Linked Immunosorbent Assay Using Recombinant Major Surface Protein 5 总被引:3,自引:0,他引:3 下载免费PDF全文
Susana Torioni de Echaide Donald P. Knowles Travis C. McGuire Guy H. Palmer Carlos E. Suarez Terry F. McElwain 《Journal of clinical microbiology》1998,36(3):777-782
A competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5 (rMSP5-cELISA) of Anaplasma marginale was validated in a naturally infected cattle herd in an area of eastern Oregon where A. marginale is endemic. The true positive and negative A. marginale infection status of 235 randomly selected cattle was determined by using a nested PCR (nPCR) coupled with msp5 sequence analysis and hybridization. Judgment of the reliability of the nPCR and hybridization for detection of persistent infections was based on three observations. First, the nPCR was able to detect as few as 30 infected erythrocytes per ml. Second, the nPCR was able to consistently detect low levels of rickettsemia in seven carrier cattle experimentally infected with A. marginale. Third, msp5 sequence analysis showed >95% identity among 30 nPCR amplicons from cattle naturally infected with field strains of A. marginale. The nPCR and hybridization identified 151 infected and 84 uninfected cattle among the 235 animals tested. With a cutoff point of 28%, the rMSP5-cELISA showed a sensitivity of 96% and a specificity of 95%. These results indicate that the rMSP5-cELISA can sensitively and specifically detect cattle with naturally acquired persistent A. marginale infections and suggest that it is an excellent assay for epidemiological studies, eradication programs, and regulation of international cattle movement. 相似文献
68.
69.
Colonial morphology of Burkholderia cepacia complex genomovar III: implications in exopolysaccharide production,pilus expression,and persistence in the mouse 下载免费PDF全文
The purpose of this study was to determine the role of colonial morphology of Burkholderia cepacia complex (BCC) organisms in pathogenicity in a mouse model of pulmonary infection. BCC strain C1394 was rapidly cleared by leukopenic mice after intranasal challenge, whereas a spontaneous variant (C1394mp2) that was indistinguishable from the parent strain by genetic typing persisted in the lungs and differed in colonial morphology. The parent strain had a matte colonial phenotype, made scant exopolysaccharide (EPS), and was lightly piliated. The variant had a shiny phenotype, produced abundant EPS, and was heavily piliated. Matte to shiny colonial transformation was induced by growth at 42 degrees C. Colonial morphology in the BCC strain variant was associated with persistence after pulmonary challenge and appeared to be correlated with the elaboration of putative virulence determinants. 相似文献
70.
Preferences for self-care or professional advice for minor illness: a discrete choice experiment 下载免费PDF全文
Terry Porteous Mandy Ryan Christine M Bond Phil Hannaford 《The British journal of general practice》2006,56(533):911-917
AIM: To determine the relative importance of factors that influence decision making in the management of minor illness, and how people trade between these factors. DESIGN OF STUDY: Discrete choice experiment.Setting:Scottish electoral roll. METHOD: Six hundred and fifty-two responders of a previous national survey were invited to complete a discrete choice experiment questionnaire. This was used to measure relative preferences for managing symptoms of minor illness often associated with analgesic use. Three attributes were identified as important to participants: type of management, availability, and cost of managing symptoms. Trade-offs between these attributes were examined. RESULTS: A 57% response rate was achieved (51% valid response rate). People preferred to manage symptoms by self-care and were willing to pay almost pounds 23 to do so. Community pharmacy was the preferred source of advice. Responders preferred less waiting time and paying less money when managing symptoms, and were willing to trade between factors. A less preferred type of management became more attractive when waiting times and cost were reduced. CONCLUSION: Findings suggest that self-care is the preferred method of managing symptoms of minor illness. When developing services to support self-care, policy makers should invest in services that reduce waiting times and incur least cost to users. 相似文献