全文获取类型
收费全文 | 3218篇 |
免费 | 204篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 79篇 |
妇产科学 | 92篇 |
基础医学 | 308篇 |
口腔科学 | 60篇 |
临床医学 | 242篇 |
内科学 | 758篇 |
皮肤病学 | 75篇 |
神经病学 | 133篇 |
特种医学 | 223篇 |
外科学 | 535篇 |
综合类 | 65篇 |
一般理论 | 1篇 |
预防医学 | 305篇 |
眼科学 | 48篇 |
药学 | 221篇 |
中国医学 | 11篇 |
肿瘤学 | 284篇 |
出版年
2023年 | 25篇 |
2022年 | 44篇 |
2021年 | 125篇 |
2020年 | 70篇 |
2019年 | 79篇 |
2018年 | 116篇 |
2017年 | 116篇 |
2016年 | 109篇 |
2015年 | 87篇 |
2014年 | 118篇 |
2013年 | 163篇 |
2012年 | 183篇 |
2011年 | 207篇 |
2010年 | 111篇 |
2009年 | 79篇 |
2008年 | 145篇 |
2007年 | 167篇 |
2006年 | 167篇 |
2005年 | 158篇 |
2004年 | 125篇 |
2003年 | 118篇 |
2002年 | 113篇 |
2001年 | 46篇 |
2000年 | 51篇 |
1999年 | 47篇 |
1998年 | 32篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 19篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 40篇 |
1991年 | 54篇 |
1990年 | 40篇 |
1989年 | 30篇 |
1988年 | 41篇 |
1987年 | 36篇 |
1986年 | 33篇 |
1985年 | 34篇 |
1984年 | 28篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 17篇 |
1978年 | 20篇 |
1977年 | 13篇 |
1974年 | 18篇 |
1973年 | 15篇 |
1968年 | 11篇 |
排序方式: 共有3462条查询结果,搜索用时 62 毫秒
51.
Delwel R; van Buitenen C; Salem M; Bot F; Gillis S; Kaushansky K; Altrock B; Lowenberg B 《Blood》1989,74(2):586-593
In this study, we further established the role of interleukin-1 (IL-1) alpha and IL-1 beta as regulators of proliferation of acute myeloid leukemia (AML) cells. IL-1 stimulated tritiated thymidine (3H-TdR) uptake of AML cells in 13 of 28 cases. Cytogenetic analysis confirmed the leukemic clonality of the IL-1-stimulated cells. Most likely, IL-1 exerted these stimulative effects directly on AML blast cells because IL-1 effectively induced 3H-TdR uptake of CD34-positive AML blasts (separated following cell sorting). Furthermore, adherent cell-depleted AML samples of three patients were more effectively stimulated than nondepleted AML fractions. Cluster and colony formation from adherent cell depleted AML samples could also be stimulated with IL-1, ie, in seven of ten cases analyzed. Subsequent experiments indicated that IL-1 stimulation depended on the release of GM-CSF because (1) induction of DNA synthesis of AML cells by IL-1 could be abrogated with antigranulocyte-macrophage colony-stimulating factor (GM-CSF) antibody, (2) conditioned media (CM) prepared from IL-1 stimulated AML blasts (adherent cell depleted) could stimulate the proliferation of purified normal bone marrow progenitors whereas supernatants from nonstimulated AML blasts did not, and (3) GM-CSF was demonstrated in IL-1/AML-CM with a specific radioimmunoassay, while GM-CSF was not detectable in nonstimulated supernatants. In one case of AML showing significant 3H- TdR uptake in the absence of CSFs, this spontaneous DNA synthesis was found to depend on autocrine IL-1 beta release as it could be suppressed with anti-IL-1 beta antibody or anti-GM-CSF. The blockade by anti-IL-1 beta could be overcome by the addition of high concentrations of IL-1 beta as well as GM-CSF. Thus, in this particular case, endogenously produced IL-1 beta had stimulated the release of GM-CSF which resulted in GM-CSF-dependent proliferation. The results indicate that GM-CSF production by AML blasts is often regulated by IL-1 rather than being constitutive. 相似文献
52.
53.
54.
N. A. Habib M. J. Hershman R. Salem W. Barker K. Apostolov C. B. Wood 《International journal of colorectal disease》1987,2(1):12-14
Our previous studies have demonstrated a desaturation of stearic acid related to oleic acid in the lipid layer of erythrocytes in patients with malignancies. This study investigated the stearic acid desaturation in red blood cell membranes of rats during the induction of colorectal tumours. Male Sprague-Dawley rats were injected weekly with dimethylhydrazine (DMH) and sacrificed at 4-week intervals. Blood was withdrawn via heart puncture, collected in EDTA bottle and erythrocytes separated by centrifugation. Total lipid extraction was carried out and analysed with gas liquid chromatography. In the control rats (injected with normal saline) the mean of the stearic to oleic acid ratio in erythrocyte membranes was 2.0±0.3 (n=28, range 1.51–2.62) compared to a mean of 0.94±0.16 (n=0.5–1.23) in tumour bearing rats (p< 0.001). The increased desaturation occurred in parallel with appearance of tumours. These data suggest the regulation of stearic acid desaturation is an important adaptive mechanism of membrane fluidity and could be a useful chemical marker for malignancy. 相似文献
55.
M A Salem 《Endocrinology》1988,123(3):1565-1576
A naturally occurring pituitary peptide, human (h) GH-(1-43) potentiates insulin action. The present study has compared the effects of acute (30-60 min) and chronic (3-6 days) injections of synthetic hGH-(1-43), hGH, and insulin in normal, diabetic, hypophysectomized, and diabetic-hypophysectomized rats. Male rats (150-250 g) received injections of saline, insulin (50-200 mU), hGH (200 micrograms), or hGH-(1-43) (200-400 micrograms) with or without insulin. Hormone and glucose were injected simultaneously for glucose tolerance tests. Basal and insulin-stimulated [U-14C]glucose oxidation to 14CO2 in adipose tissue were measured in vitro after in vivo treatments; insulin release by isolated pancreatic islets was determined in vitro. Acute injections of hGH-(1-43) with insulin dramatically increased glucose clearance in diabetic (P less than 0.05) and hypophysectomized (P less than 0.01) rats. In diabetic-hypophysectomized rats acute injections of hGH-(1-43) significantly lowered the elevated basal blood glucose level (P less than 0.025) and stimulated [U-14C]glucose oxidation to 14CO2 in adipose tissue (P less than 0.05); it did not increase the glucose clearance rate during glucose administration. Chronic treatment of diabetic rats with hGH-(1-43) did not lower the elevated blood glucose level significantly, but it stimulated [U-14C]glucose oxidation to 14CO2 in adipose tissue; the oxidation was further stimulated by treatment with insulin. Chronic injections of hGH-(1-43) slightly lowered blood glucose levels in hypophysectomized rats (P less than 0.025) despite a diminished release in vitro of insulin from pancreatic islets (P less than 0.05). Therefore, these experiments show hGH-(1-43) to be an insulin potentiator that increases insulin-stimulated glucose clearance and glucose oxidation without an increase in insulin secretion, and they suggest that the peptide may have a physiological role in regulating carbohydrate metabolism. 相似文献
56.
Aim of the work
To investigate sleep problems in rheumatoid arthritis (RA) patients and to correlate sleep scores with disease characteristics and activity.Patients and methods
100 RA patients and 40 matched controls were included. Disease activity score (DAS28), visual analogue scale (VAS) for pain, modified health assessment questionnaire (MHAQ) and medical outcomes study short form-36 (SF-36) were assessed and the van der Heijde-modified Sharp score (vdHSS) calculated. The Pittsburgh Sleep Quality Index (PSQI) was used to investigate the sleeping habits, sleep difficulty was assessed using the Athens Insomnia Scale (AIS) and daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS).Results
The patients were 84 females and 16 males (F:M 5.25:1) with mean age of 48.1 ± 12.4 years, disease duration of 6.9 ± 5.9 years, DAS28 was 4.3 ± 1.4, MHAQ was 0.95 ± 0.6 and VAS was 45.2 ± 21.1. The sleep scores PSQI, AIS and ESS were significantly increased in patients (6.98 ± 2.8, 9.6 ± 4.4 and 7.4 ± 2.6) compared to control (2.6 ± 1.9, 2.7 ± 1.8 and 3.3 ± 2.03 respectively; p = 0.01 each). Sleep scores tended to be lower in females and were significantly higher in those with positive C-reactive protein. Rheumatoid factor positive patients and those not receiving methotrexate had significantly higher PSQI and AIS scores. Sleep scores significantly correlated with age, erythrocyte sedimentation rate, DAS28, VAS, MHAQ and vdHSS and negatively with SF-36 physical component score (PCS) (p = 0.01 for all). Disease duration, DAS28, VAS and SF36 (PCS) were significant risk factors for sleep problems.Conclusion
A high frequency of sleep disturbances in RA patients was observed. Interplay of pain, fatigue, activity and disability may lead to poor sleep quality. 相似文献57.
Seewald S Brand B Groth S Omar S Mendoza G Seitz U Yasuda I Xikun H Nam VC Xu H Thonke F Soehendra N 《Gastrointestinal endoscopy》2004,59(4):463-470
BACKGROUND: The treatment of pancreatic fistula can be difficult. A novel endoscopic approach to sealing pancreatic fistulas by using N-butyl-2-cyanoacrylate is described. METHODS: Twelve patients with pancreatic fistulas underwent endoscopic injection of N-butyl-2-cyanoacrylate into the fistulous tract, in addition to endoscopic drainage. RESULTS: Fistulas were closed successfully in 8 of 12 patients. A single treatment session was successful in 7 patients; a second session was required in one patient. In two patients, closure was temporary, and, in one patient, the treatment failed. One patient died 24 hours after treatment. He developed a pulmonary thromboembolism from a left popliteal vein thrombosis and died from complications of surgical thromboembolectomy. At autopsy, a pulmonary embolus was found, but there was no evidence of N-butyl-2-cyanoacrylate in the lungs. No procedure-related complication occurred over a median follow-up of 20.7 months (range 9-51 months). CONCLUSIONS: In this preliminary study, occlusion of pancreatic fistulas by using N-butyl-2-cyanoacrylate glue was safe and effective, and obviated the need for surgery in a substantial proportion of patients. Further studies of the use of N-butyl-2-cyanoacrylate for closure of pancreatic fistula are warranted. 相似文献
58.
Guerra N Michel F Gati A Gaudin C Mishal Z Escudier B Acuto O Chouaib S Caignard A 《Blood》2002,100(8):2874-2881
Renal cell carcinoma (RCC) infiltrating lymphocytes (TILs) express killer cell immunoglobulinlike receptors (KIRs) that inhibit the antitumor CD8(+) T-cell lysis. In the present study, to better examine the functional consequences of KIR engagement on cytotoxic T lymphocyte (CTL)/tumor interaction, we have investigated the influence of KIR CD158a on early steps of T-cell activation. We show that coengagement of T-cell receptor (TCR) and CD158a by tumor cells inhibited tyrosine phosphorylation of early signaling proteins ZAP-70 and LAT, lipid raft coalescence, and TCR/CD3 accumulation at the CTL/tumor cell interface. In addition, the guanine exchange factor Vav was not phosphorylated, and no actin cytoskeleton rearrangement was observed. Our data indicate a role of KIR CD158a in the dynamic events induced by TCR triggering, preventing CTL membrane reorganization, and subsequent completion of CTL activation program. Accordingly, the expression of CD158 by TILs may favor tumor cell escape to the immune response. 相似文献
59.
Katayoun Salem Hossein Khoshrang Maryam Kousha Mahboobeh Hoseini Marzieh Ranjbar Shadi Baniasadi Jamshid Salamzadeh 《Iranian journal of pediatrics.》2015,25(3)
Background:
Among different categories of sedative agents, benzodiazepines have been prescribed for more than three decades to patients of all ages. The effective and predictable sedative and amnestic effects of benzodiazepines support their use in pediatric patients. Midazolam is one of the most extensively used benzodiazepines in this age group. Oral form of drug is the best accepted route of administration in children.Objectives:
The purpose of this study was to compare the efficacy and safety of a commercially midazolam syrup versus orally administered IV midazolam in uncooperative dental patients. Second objective was to determine whether differences concerning sedation success can be explained by child‘s behavioral problems and dental fear.Patients and Methods:
Eighty eight uncooperative dental patients (Frankl Scales 1,2) aged 3 to 6 years, and ASA I participated in this double blind, parallel randomized, controlled clinical trial. Midazolam was administered in a dose of 0.5 mg/kg for children under the age 5 and 0.2 mg/kg in patients over 5 years of age. Physiologic parameters including heart rate, respiratory rate, oxygen saturation and blood pressure were recorded. Behavior assessment was conducted throughout the course of treatment using Houpt Sedation Rating Scale and at critical moments of treatment (injection and cavity preparation) by North Carolina Scale. Dental fear and behavioral problems were evaluated using Child Fear Schedule Survey-Dental Subscale (CFSS-DS), and Strength and Difficulties Questionnaire (SDQ). Independent t-test, Chi-Square, and Pearson correlation were used for statistical analysis.Results:
Acceptable overall sedation ratings were observed in 90% and 86% of syrup and IV/Oral group respectively; Chi-Square P = 0.5. Other domains of Houpt Scale including: sleep, crying and movement were also not significantly different between groups. Physiological parameters remained in normal limits during study without significant difference between groups.Conclusions:
“Orally administered IV midazolam” preparation can be used as an alternative for commercially midazolam syrup. 相似文献60.