全文获取类型
收费全文 | 31778篇 |
免费 | 1848篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 251篇 |
儿科学 | 1098篇 |
妇产科学 | 915篇 |
基础医学 | 3582篇 |
口腔科学 | 390篇 |
临床医学 | 5824篇 |
内科学 | 5307篇 |
皮肤病学 | 343篇 |
神经病学 | 3127篇 |
特种医学 | 600篇 |
外国民族医学 | 1篇 |
外科学 | 3016篇 |
综合类 | 295篇 |
现状与发展 | 1篇 |
一般理论 | 50篇 |
预防医学 | 4475篇 |
眼科学 | 444篇 |
药学 | 1848篇 |
中国医学 | 33篇 |
肿瘤学 | 2125篇 |
出版年
2023年 | 194篇 |
2022年 | 326篇 |
2021年 | 588篇 |
2020年 | 420篇 |
2019年 | 656篇 |
2018年 | 805篇 |
2017年 | 559篇 |
2016年 | 633篇 |
2015年 | 669篇 |
2014年 | 989篇 |
2013年 | 1588篇 |
2012年 | 2292篇 |
2011年 | 2424篇 |
2010年 | 1284篇 |
2009年 | 1126篇 |
2008年 | 2188篇 |
2007年 | 2387篇 |
2006年 | 2271篇 |
2005年 | 2204篇 |
2004年 | 2034篇 |
2003年 | 1954篇 |
2002年 | 1865篇 |
2001年 | 218篇 |
2000年 | 182篇 |
1999年 | 278篇 |
1998年 | 371篇 |
1997年 | 309篇 |
1996年 | 244篇 |
1995年 | 274篇 |
1994年 | 213篇 |
1993年 | 210篇 |
1992年 | 131篇 |
1991年 | 136篇 |
1990年 | 134篇 |
1989年 | 111篇 |
1988年 | 102篇 |
1987年 | 94篇 |
1986年 | 92篇 |
1985年 | 103篇 |
1984年 | 124篇 |
1983年 | 126篇 |
1982年 | 144篇 |
1981年 | 139篇 |
1980年 | 118篇 |
1979年 | 56篇 |
1978年 | 71篇 |
1977年 | 61篇 |
1976年 | 47篇 |
1975年 | 36篇 |
1974年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Lucy Yardley David Papo Adolfo Bronstein Michael Gresty Mark Gardner Nilli Lavie Linda Luxon 《Neuropsychologia》2002,40(4):373-383
The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information. 相似文献
22.
23.
Multivitamin and alcohol intake and folate receptor alpha expression in ovarian cancer. 总被引:2,自引:0,他引:2
Linda E Kelemen Thomas A Sellers Gary L Keeney Wilma L Lingle 《Cancer epidemiology, biomarkers & prevention》2005,14(9):2168-2172
Folate receptor alpha (FRalpha) expression in epithelial ovarian cancer may be related to folate intake. We examined this association using multivitamin intake, a proxy for folic acid, and assessed whether the relation was modified by alcohol intake, a folate agonist. Cases (n = 148) with suspected epithelial ovarian cancer, of ages > or = 20 years, were seen at Mayo Clinic, Minnesota, between 2000 and 2004; those with tumor specimens (n = 108) were included in analyses. Outpatient controls (n = 148) without cancer and with at least one ovary intact were matched to cases by age (within 5 years) and state of residence. Multivitamin (> or = 4 pills/wk) and weekly alcohol (> or = 5 drinks) intakes were assessed. Tumor specimens were analyzed immunohistochemically for FRalpha. Multivariable rate ratios (RR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression. In case-control analysis, the RRs of multivitamin intake with absent/weak/moderate and strong-expressing FRalpha tumors were 0.30 (95% CI, 0.12-0.70) and 0.47 (95% CI, 0.24-0.91), respectively. For alcohol, the associations were 0.84 (95% CI, 0.24-2.86) and 1.65 (95% CI, 0.69-3.93), respectively. In case-case analysis, the RR associated with developing strong-expressing versus other FRalpha tumors was 3.13 (95% CI, 1.14-8.65) for multivitamins and 1.58 (95% CI, 0.45-5.60) for alcohol. The data did not support evidence for an interaction between multivitamin and alcohol intake with risk of developing a strong-expressing FRalpha tumor. The association of multivitamin intake with ovarian cancer may depend on FRalpha expression level. 相似文献
24.
Nonorganic failure-to-thrive is a medical-psychological disorder reflecting lack of growth in an infant without apparent physical causes. Children who fail to thrive as infants are at high risk for developmental delays, personality problems, abuse, and death. This article focuses on environmental failure-to-thrive, describing the behavioral characteristics of the nonthriving infant and the family milieu. Aspects of early environments of NOFT infants are profiled, specific intervention strategies are discussed, and recommendations regarding the promotion of intense, consistent multi-disciplinary intervention strategies are advanced. 相似文献
25.
The galanin peptide family and its three receptors have with compelling evidence been implicated in several high-order physiological disorders. The co-localization with other neuromodulators and the distinct up-regulation during and after pathological disturbances has drawn attention to this neuropeptide family. In the current study we present data on receptor binding and functional response for a novel galanin receptor type 2 (GalR2) selective chimeric peptide, M1145 [(RG)2-N-galanin(2-13)-VL-(P)3-(AL)2-A-amide]. The M1145 peptide shows more than 90-fold higher affinity for GalR2 over GalR1 and a 76-fold higher affinity over GalR3. Furthermore, the peptide yields an agonistic effect in vitro, seen as an increase in inositol phosphate (IP) accumulation, both in the absence or the presence of galanin. The peptide design with a N-terminal extension of galanin(2-13), prevails new insights in the assembly of novel subtype specific ligands for the galanin receptor family and opens new possibilities to apply the galanin system as a putative drug target. 相似文献
26.
27.
Cannabis remains the most widely used illegal drug in the United States. This update examines the available literature on neuroimaging studies of the brains of cannabis users. The majority of studies examining the acute effects of delta-9-tetrahydrocannabinol (THC) administration used PET methods and concluded that administration of THC leads to increased activation in frontal and paralimbic regions and the cerebellum. These increases in activation are broadly consistent with the behavioral effects of the drug. Although there is only equivocal evidence that chronic cannabis use might result in structural brain changes, blood-oxygenation-level-dependent-fMRI studies in chronic users consistently show alterations, or neuroadaptation, in the activation of brain networks responsible for higher cognitive functions. It is not yet certain whether these changes are reversible with abstinence. Given the high prevalence of cannabis use among adolescents, studies are needed to evaluate whether cannabis use might affect the developing brain. Considerable further work, employing longitudinal designs, is also required to determine whether cannabis use causes permanent functional alterations in the brains of adults. 相似文献
28.
Cystic Fibrosis has effects on many body systems, including the skeletal system. In this case, we describe the impact of respiratory and endocrine disease on bone healing following orthopedic trauma in a 22-year-old woman. Limitations to mobility resulting from trauma complicated her respiratory condition. Disease-related effects on bone health and healing delayed her recovery from the trauma. It is important to recognize the multisystemic nature of CF, even when managing acute orthopedic injuries. 相似文献
29.
David Berrigan Linda W Pickle Jennifer Dill 《International journal of health geographics》2010,9(1):20
Background
Past studies of associations between measures of the built environment, particularly street connectivity, and active transportation (AT) or leisure walking/bicycling have largely failed to account for spatial autocorrelation of connectivity variables and have seldom examined both the propensity for AT and its duration in a coherent fashion. Such efforts could improve our understanding of the spatial and behavioral aspects of AT. We analyzed spatially identified data from Los Angeles and San Diego Counties collected as part of the 2001 California Health Interview Survey. 相似文献30.
The trypanosome responsible for the majority of cases of human trypanosomiasis in Africa is Group 1 Trypanosoma brucei gambiense. Currently the most reliable test for the parasite is based on a single gene, which encodes a 47 kDa receptor-like T. b. gambiense-specific glycoprotein, TgsGP, expressed in the flagellar pocket of bloodstream forms. Although TgsGP has been demonstrated in T. b. gambiense throughout its geographic range, similar genes have been demonstrated in other T. brucei sspp. isolates, and there are no data on the extent of sequence variation in TgsGP. Here we have carried out a comparison of TgsGP sequences in a range of Group 1 T. b. gambiense isolates and compared the gene to homologues in other T. brucei sspp. in order to provide information to support the use of this gene as the key identification target for Group 1 T. b. gambiense. We demonstrate that the sequence of TgsGP is well conserved in Group 1 T. b. gambiense across the endemic range of gambian human trypanosomiasis and confirm that this gene is a suitable target for specific detection of this parasite. The TgsGp-like genes in some isolates of T. b. brucei, T. b. rhodesiense and Group 2 T. b. gambiense are closely similar to VSG Tb10.v4.0178, which may be the ancestral gene from which TgsGP was derived. 相似文献