全文获取类型
收费全文 | 15286篇 |
免费 | 998篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 489篇 |
妇产科学 | 989篇 |
基础医学 | 1848篇 |
口腔科学 | 107篇 |
临床医学 | 2127篇 |
内科学 | 2696篇 |
皮肤病学 | 216篇 |
神经病学 | 1364篇 |
特种医学 | 309篇 |
外科学 | 1374篇 |
综合类 | 169篇 |
一般理论 | 16篇 |
预防医学 | 2029篇 |
眼科学 | 179篇 |
药学 | 974篇 |
中国医学 | 15篇 |
肿瘤学 | 1304篇 |
出版年
2023年 | 99篇 |
2022年 | 152篇 |
2021年 | 332篇 |
2020年 | 220篇 |
2019年 | 380篇 |
2018年 | 409篇 |
2017年 | 312篇 |
2016年 | 336篇 |
2015年 | 393篇 |
2014年 | 507篇 |
2013年 | 774篇 |
2012年 | 1190篇 |
2011年 | 1169篇 |
2010年 | 610篇 |
2009年 | 582篇 |
2008年 | 941篇 |
2007年 | 1098篇 |
2006年 | 1024篇 |
2005年 | 1029篇 |
2004年 | 910篇 |
2003年 | 882篇 |
2002年 | 755篇 |
2001年 | 107篇 |
2000年 | 63篇 |
1999年 | 118篇 |
1998年 | 155篇 |
1997年 | 113篇 |
1996年 | 92篇 |
1995年 | 104篇 |
1994年 | 83篇 |
1993年 | 73篇 |
1992年 | 46篇 |
1991年 | 38篇 |
1990年 | 39篇 |
1989年 | 30篇 |
1988年 | 37篇 |
1987年 | 37篇 |
1986年 | 30篇 |
1985年 | 25篇 |
1984年 | 42篇 |
1983年 | 30篇 |
1982年 | 43篇 |
1981年 | 40篇 |
1980年 | 30篇 |
1975年 | 227篇 |
1973年 | 123篇 |
1971年 | 92篇 |
1967年 | 52篇 |
1965年 | 38篇 |
1963年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Localization of IFN-gamma-activated Stat1 and IFN regulatory factors 1 and 2 in breast cancer cells.
Judith M Connett Steven R Hunt Suzanne M Hickerson Susan J Wu Gerard M Doherty 《Journal of interferon & cytokine research》2003,23(11):621-630
The aim of the present work was to evaluate the induction and localization of Stat1, interferon (IFN) regulatory factor-1 (IRF-1), and IRF-2 after IFN-gamma exposure of human breast cancer cell lines, SKBR3, MDA468, MCF7, and BT20. Results from growth assays, Western staining, electrophoretic mobility shift assay (EMSA), and immunohistochemical staining were collated to test our hypothesis that immunohistochemical analysis of Stat1, IRF-1, and IRF-2 would provide additional information about the functionality of the IFN-gamma signaling pathway in human tumor lines. EMSA results showed that in each of four cell lines, Stat1 expression was increased and demonstrated functional activity after IFN-gamma stimulation. Western and EMSA analysis showed upregulation of IRF-1 but not IRF-2 in each cell line. Confocal microscopy of cells stained for Stat1, IRF-1, and IRF-2 confirmed the results and also provided novel information about the intracellular localization of proteins and intercellular variations in responses. The proportion of cells with IRF-1 stimulation and translocation was positively correlated with the IFN-gamma growth suppression in vitro. In conclusion, using four independent assays, we have demonstrated that heterogeneity in IFN-gamma-mediated upregulation of signal transduction proteins can be detected in vitro and that these differences can explain distinct cellular growth effects. 相似文献
82.
Marla Gearing Johannes Tigges Hiroshi Mori Suzanne S. Mirra 《Neurobiology of aging》1996,17(6):54-908
Because aged nonhuman primates show β-amyloid (Aβ) deposition in senile plaques and blood vessels similar to that seen in human aging and AD, we used C-terminal specific antibodies to Aβ40 and Aβ42 to investigate Aβ peptide length in the brains of 11 aged rhesus monkeys and a 59-year-old chimpanzee. In contrast to AD, where the earliest and most prominent form of Aβ in senile plaques is Aβ42, in the monkey, Aβ40-positive plaques predominated. The ratio of Aβ4): Aβ42-positive plaques averaged 2.08 in the monkey, as compared to a mean ratio of 0.37 in 68 human AD subjects (p < 0.001). Aβ40 was also more prominent in the chimpanzee than in humans. Possible explanations for these findings include species differences in the cleavage of Aβ from the amyloid precursor protein or in the activity of a putative carboxy peptidase forming Aβ40 from Aβ42 in situ. 相似文献
83.
Adherence-Facilitating Behaviors of a Multidisciplinary Pediatric Rheumatology Staff 总被引:1,自引:0,他引:1
Thompson Suzanne M.; Dahlquist Lynnda M.; Koenning Gaye M.; Bartholomew L. Kay 《Journal of pediatric psychology》1995,20(3):291-297
Investigated the behaviors of pediatric rheumatology healthcare providers that were expected to be related to patient orparent adherence. Medical charts of 108 patients ages 1 to 20years diagnosed with Juvenile Rheumatoid Arthritis were examined.The 473 outpatient visits over 15 months yielded a total of2,578 treatment recommendations, but only 1,390 adherence-facilitatingbehaviors by medical staff were documented. Providing informationabout how often to perform the recommendation was the most commonstaff behavior. In contrast, care providers rarely indicatedthat they addressed their patients' concerns and barriers toimplementing the recommendations, or employed behavior modificationstrategies to increase adherence. Implications of these findingsfor development of programs designed to increase treatment adherencein children with chronic diseases requiring time-consuming,intrusive medical regimens are discussed. 相似文献
84.
Development of capture assays for different modifications of human low-density lipoprotein 总被引:2,自引:0,他引:2
Virella G Derrick MB Pate V Chassereau C Thorpe SR Lopes-Virella MF 《Clinical and diagnostic laboratory immunology》2005,12(1):68-75
Antibodies to malondialdehyde (MDA)-modified low-density lipoprotein (LDL), copper-oxidized LDL (oxLDL), Nepsilon(carboxymethyl) lysine (CML)-modified LDL, and advanced glycosylation end product (AGE)-modified LDL were obtained by immunization of rabbits with in vitro-modified human LDL preparations. After absorption of apolipoprotein B (ApoB) antibodies, we obtained antibodies specific for each modified lipoprotein with unique patterns of reactivity. MDA-LDL antibodies reacted strongly with MDA-LDL and also with oxLDL. CML-LDL antibodies reacted strongly with CML-LDL and also AGE-LDL. oxLDL antibodies reacted with oxLDL but not with MDA-LDL, and AGE-LDL antibodies reacted with AGE-LDL but not with CML-LDL. Capture assays were set with each antiserum, and we tested their ability to capture ApoB-containing lipoproteins isolated from precipitated immune complexes (IC) and from the supernatants remaining after IC precipitation (free lipoproteins). All antibodies captured lipoproteins contained in IC more effectively than free lipoproteins. Analysis of lipoproteins in IC by gas chromatography-mass spectrometry showed that they contained MDA-LDL and CML-LDL in significantly higher concentrations than free lipoproteins. A significant correlation (r=0.706, P<0.019) was obtained between the MDA concentrations determined by chemical analysis and by the capture assay of lipoproteins present in IC. In conclusion, we have developed capture assays for different LDL modifications in human ApoB/E lipoprotein-rich fractions isolated from precipitated IC. This approach obviates the interference of IC in previously reported modified LDL assays and allows determination of the degree of modification of LDL with greater accuracy. 相似文献
85.
Joyce PR Porter RJ Mulder RT Luty SE McKenzie JM Miller AL Kennedy MA 《Psychological medicine》2005,35(4):511-517
BACKGROUND: Although diurnal variation of mood is a widely recognized symptom of depression, the clinical, neurobiological and psychopharmacological significance of this symptom has not previously been reported. METHOD: A total of 195 depressed out-patients underwent a detailed clinical and neurobiological assessment, and were then randomized to treatment with either fluoxetine or nortriptyline. RESULTS: Of the 195 depressed patients, 62 had a pattern of reversed diurnal variation (i.e. worse in the evening). Those with reversed diurnal variation had a poorer response to a serotonergic anti-depressant, were less likely to have bipolar II disorder, had a higher tryptophan: large neutral amino acid ratio and had different allele frequencies of the polymorphisms in the promoter region of the serotonin transporter. CONCLUSIONS: These findings raise the possibility of serotonergic influence on diurnal variation, and that the symptom of reversed diurnal variation is of relevance to antidepressant prescribing. 相似文献
86.
Hilary Pinnock Lorraine Adlem Suzanne Gaskin Jan Harris Caroline Snellgrove Aziz Sheikh 《The British journal of general practice》2007,57(542):714-722
BACKGROUND: Attendance for routine asthma reviews is poor. A recent randomised controlled trial found that telephone consultations can cost-effectively and safely enhance asthma review rates; however, concerns have been expressed about the generalisability and implementation of the trial's findings. AIM: To evaluate the effectiveness of a telephone option as part of a routine structured asthma review service. DESIGN OF STUDY: Phase IV controlled before-and-after implementation study. SETTING: A large UK general practice. METHOD: Using existing administrative groups, all patients with active asthma (n = 1809) received one of three asthma review services: structured recall with a telephone-option for reviews versus structured recall with face-to-face-only reviews, or usual-care (to assess secular trends). Main outcome measures were: proportion of patients with active asthma reviewed within the previous 15 months (Quality and Outcomes Framework target), mode of review, enablement, morbidity, and costs to the practice. RESULTS: A routine asthma review was provided for 397/598 (66.4%) patients in the telephone-option group compared with 352/654 (53.8%) in the face-to-face-only review group: risk difference 12.6% (95% confidence interval [CI] = 7.2 to 17.9, P<0.001). The usual-care group achieved a review rate of 282/557 (50.6%). Morbidity was equivalent in the three groups; however, enablement (P = 0.03) and confidence (P = 0.007) in asthma management were greater in the telephone-option versus face-to-face-only group. The cost per review achieved by providing the telephone-option service was lower than the face-to-face-only service (10.03 pounds versus 12.74 pounds, mean difference 2.71 pounds; 95% CI = 1.92 to 3.50, P<0.001); usual-care costs were 11.85 pounds per review achieved. CONCLUSION: Routinely offering telephone reviews cost-effectively increased asthma review rates, enhancing patient enablement and confidence with management, with no detriment to asthma morbidity. Practices should consider a telephone option for their asthma review service. 相似文献
87.
Interleukin-17: an emerging role in lung inflammation 总被引:5,自引:0,他引:5
88.
Recovery of the endogenous beta cell function in the NOD model of autoimmune diabetes 总被引:7,自引:0,他引:7
Zorina TD Subbotin VM Bertera S Alexander AM Haluszczak C Gambrell B Bottino R Styche AJ Trucco M 《Stem cells (Dayton, Ohio)》2003,21(4):377-388
In light of accumulating evidence that the endocrine pancreas has regenerative properties and that hematopoietic chimerism can abrogate destruction of beta cells in autoimmune diabetes, we addressed the question of whether recovery of physiologically adequate endogenous insulin regulation could be achieved in the nonobese diabetic (NOD) mice rendered allogeneic chimerae. Allogeneic bone marrow (BM) was transplanted into NOD mice at the preclinical and overtly clinical stages of the disease using lethal and nonlethal doses of radiation for recipient conditioning. Islets of Langerhans, syngeneic to the BM donors, were transplanted under kidney capsules of the overtly diabetic animals to sustain euglycemia for the time span required for recovery of the endogenous pancreas. Nephrectomies of the graft-bearing organs were performed 14 weeks later to confirm the restoration of endogenous insulin regulation. Reparative processes in the pancreata were assessed histologically and immunohistochemically. The level of chimerism in NOD recipients was evaluated by flow cytometric analysis. We have shown that as low as 1% of initial allogeneic chimerism can reverse the diabetogenic processes in islets of Langerhans in prediabetic NOD mice, and that restoration of endogenous beta cell function to physiologically sufficient levels is achievable even if the allogeneic BM transplantation is performed after the clinical onset of diabetes. If the same pattern of islet regeneration were shown in humans, induction of an autoimmunity-free status by establishment of a low level of chimerism, or other alternative means, might become a new therapy for type 1 diabetes. 相似文献
89.
Wajid M Abbasi AA Ansar M Pham TL Yan K Haque S Ahmad W Leal SM 《European journal of human genetics : EJHG》2003,11(10):812-815
This article describes the identification of a novel locus (DFNB39) responsible for an autosomal recessive form of hearing loss segregating in a Pakistani consanguineous family. The hearing impaired members of this family present with profound prelingual sensorineural hearing impairment and use sign language for communications. Linkage was established to microsatellite markers located on chromosome 7q with a maximum multipoint lod score of 3.8. The region of homozygosity spans a 19 cM region that is bounded by markers D7S3046 and D7S644. 相似文献
90.
Suzanne Morrison David S. Gardner rew J. W. Fletcher Malcolm R. Bloomfield Dino A. Giussani 《The Journal of physiology》2003,547(1):283-291
We tested the hypothesis that enhanced nitric oxide (NO) opposes fetal peripheral vasoconstrictor responses to acute hypoxaemia via actions involving the carotid chemoreflex and the adrenal medulla. The hypothesis was tested in the late gestation ovine fetus using a novel NO clamp technique, which involves fetal combined treatment with the NO synthase inhibitor, l -NAME, and the NO donor, sodium nitroprusside. In contrast to treatment with l -NAME alone, combined fetal treatment with l -NAME and nitroprusside prevents generalized vasoconstriction and pronounced hypertension, not only maintaining basal cardiovascular function, but also permitting blockade of the de novo synthesis of NO during hypoxaemia while compensating for the tonic production of the gas. Under general anaesthesia, seven sheep fetuses were surgically prepared with catheters and a femoral Transonic flow probe. Five days after surgery, fetuses were subjected to a 3 h protocol: 1 h normoxia, 1 h hypoxaemia and 1 h recovery. Fetal hypoxaemia was induced during either fetal infusion with saline or treatment with the NO clamp. During saline infusion, fetuses responded to hypoxaemia with transient bradycardia, femoral vasoconstriction and increases in plasma noradrenaline and adrenaline. During fetal treatment with the NO clamp, bradycardia persisted and there were greater peripheral vasoconstrictor and catecholaminergic responses to hypoxaemia. Further analysis showed that NO clamp treatment enhanced the chemoreflex component of the fetal cardiovascular defence to acute hypoxaemia. These data support the hypothesis that enhanced NO synthesis during acute hypoxaemia offsets fetal peripheral vasoconstrictor responses to hypoxaemia via chemoreflex and adrenomedullary actions. 相似文献