全文获取类型
收费全文 | 197599篇 |
免费 | 16167篇 |
国内免费 | 7156篇 |
专业分类
耳鼻咽喉 | 1611篇 |
儿科学 | 2575篇 |
妇产科学 | 2166篇 |
基础医学 | 30955篇 |
口腔科学 | 3293篇 |
临床医学 | 14382篇 |
内科学 | 35263篇 |
皮肤病学 | 2681篇 |
神经病学 | 14745篇 |
特种医学 | 4194篇 |
外国民族医学 | 52篇 |
外科学 | 13201篇 |
综合类 | 26095篇 |
现状与发展 | 19篇 |
一般理论 | 6篇 |
预防医学 | 9742篇 |
眼科学 | 1961篇 |
药学 | 31960篇 |
45篇 | |
中国医学 | 8156篇 |
肿瘤学 | 17820篇 |
出版年
2024年 | 522篇 |
2023年 | 3810篇 |
2022年 | 8267篇 |
2021年 | 10030篇 |
2020年 | 7536篇 |
2019年 | 6431篇 |
2018年 | 6177篇 |
2017年 | 6191篇 |
2016年 | 6319篇 |
2015年 | 7436篇 |
2014年 | 11507篇 |
2013年 | 12811篇 |
2012年 | 11364篇 |
2011年 | 13124篇 |
2010年 | 10826篇 |
2009年 | 11084篇 |
2008年 | 10750篇 |
2007年 | 9774篇 |
2006年 | 8725篇 |
2005年 | 7666篇 |
2004年 | 6390篇 |
2003年 | 5717篇 |
2002年 | 4538篇 |
2001年 | 3701篇 |
2000年 | 3125篇 |
1999年 | 2826篇 |
1998年 | 2636篇 |
1997年 | 2445篇 |
1996年 | 2188篇 |
1995年 | 1943篇 |
1994年 | 1761篇 |
1993年 | 1525篇 |
1992年 | 1280篇 |
1991年 | 1207篇 |
1990年 | 991篇 |
1989年 | 832篇 |
1988年 | 792篇 |
1987年 | 665篇 |
1986年 | 600篇 |
1985年 | 945篇 |
1984年 | 900篇 |
1983年 | 630篇 |
1982年 | 639篇 |
1981年 | 511篇 |
1980年 | 431篇 |
1979年 | 353篇 |
1978年 | 230篇 |
1977年 | 193篇 |
1976年 | 183篇 |
1975年 | 123篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Non-ionic contrast media (CM) are proven to be significantly safer than the high osmolar ionic contrast media (HOCM). Nevertheless deaths are reported after administration of non-ionic agents. The aim of the study was to investigate the rate of adverse reactions to non-ionic CM with special regard to high-risk patients and the effects of premedication with H1-and H2-receptor antagonists.In a prospective study conducted over about 2 years 12 995 examinations with intravenous or intra-arterial non-ionic CM were evaluated. Premedication with H1-and H2-antagonists was used in 1276 high-risk patients with known adverse reaction to CM, history of allergy or severe cardiac or pulmonary disease. 229 patients received no premedication inspite of known risk factors. In total, there were 143 (1.10%) adverse reactions (mild in 0.58%, moderate in 0.41% and severe in 0.05%). In high-risk patients there were adverse reactions in 4.37% without and in 1.57% with premedication. There were no severe adverse reactions in the high-risk patients after premedication. The age of the patient, CM dosage and CM concentration were not shown to be risk factors in the present study. In conclusion, the additional premedication with H1- and H2-antagonists could be an effective agent to reduce the risk of mild and moderate adverse reactions and to avoid severe adverse reactions in high-risk patients.
Correspondence to: U. Fink 相似文献
102.
C. W. Pagenkopf J-P. Bourreau C. E. Challice 《Clinical and experimental pharmacology & physiology》1990,17(8):557-565
1. Age-related changes in prejunctional alpha 2-adrenoceptors were examined in the rat vas deferens using pharmacological techniques. 2. B-HT 933 (1 x 10(-8) - 1 x 10(-6) mol/L) caused a concentration-dependent inhibition of isometric contractions (tetrodotoxin-sensitive) induced by stimulation with single field-stimulus pulses, in both the epididymal and prostatic regions of rat vas deferens. The concentration-response curve to B-HT 933 was shifted to the right with age in the prostatic regions of the vas deferens. 3. In high concentrations (10(-6) - 3 x 10(-4) mol/L), B-HT 933 caused concentration-dependent enhancement of the contractile response to stimulation and evoked spontaneous contractile activity. No significant difference in this postjunctional activity occurred with age in either the prostatic or epididymal regions of the vas deferens. 4. Schild analysis revealed no significant differences in pA2 values for the antagonisms of the prejunctional inhibitory effect of B-HT 933 by rauwolscine in either the prostatic or epididymal regions of vas deferens between young and old rats. 5. These results could be interpreted as a decrease in alpha 2-adrenoceptor number with age. The more marked decrease in the prejunctional inhibitor potency of B-HT 933 in prostatic regions of vas deferens with aging may be due to a smaller receptor reserve in this region of the vas deferens. 相似文献
103.
The treatment of neoplasia with interleukin-2 (IL-2) can be complicated by neurological deficits resembling transient Ischemic attack and stroke. We investigated whether interleukin-2 contributes to the natural course of cerebrovascular ischemia and particularly to the pathogenesis of infection-associated stroke. Plasma levels of interleukin-2 were below the level of detectability in almost all measurements. Patients with and without previous infection (n = 11, 805 ±445 U/ml vs n = 19, 824 ± 501 U/ml) did not have significantly higher levels of soluble interleukin-2 receptors than control subjects with (n = 14, 667 ± 229 U/ml) or without vascular risk factors (n = 17, 567 ± 176 U/ml). Receptor levels increased in patients during the first week after stroke (n = 15, 1157 ± 1013, p < 0.02). Levels of soluble T8 antigen (sT8) were higher in patients (n – 26, 320 ± 112 U/ml) than in healthy control subjects (n = 15, 246 ± 92 U/ml; p < 0.05) and sT8 levels increased during the first week after stroke (p < 0.05). These results reflect an immunological response to the cerebral infarct; they do not indicate a general role of the IL-2 system in the pathogenesis of ischemic stroke with or without previous infection. 相似文献
104.
J. B. Payne R. A. Reinhardt M. P. Masada L. M. DuBois A. C. Allison 《Journal of periodontal research》1993,28(6):451-453
Gingival crevicular fluid (GCF) IL-8 and IL-1,1β levels were determined by sandwich enzyme-linked immunosorbent assays. Associations between IL-8 and IL-1β GCF levels, and between these cytokines and patient estrogen status were evaluated. IL-8 and IL-1β were detected more frequently and in higher amounts/30 s GCF sample in estrogen-deficient patients than in estrogensufficient patients. IL-8 and IL-1β GCF levels were significantly correlated. These lindings suggest that GCF IL-8 levels are associated with patient estrogen status and local IL-1β concentrations. 相似文献
105.
BACKGROUND: Patient education is integral part of any diabetes therapy in Germany, but elderly patients are not able to follow the variety of topics comprising standard treatment and teaching programmes (TTP), primarily due to impaired neuropsychological function. This leads to deficits in diabetes knowledge and hindered ability for diabetes self-management. AIM: To evaluate structured TTP for geriatric patients with impaired cognitive function. PATIENTS AND METHODS: A neuropsychological examination was performed on all patients over 54 years [n=102, age 68.6 +/- 8.7 years, diabetes duration 10.3 (0.03-35.4) years, HbA1c 10.3 +/- 1.7% (HPLC, Diamat, NR 4.5-6.3%), cognitive function 87.7 +/- 12.3 IQ points] who took part in TTP for insulin therapy. Patients with impaired cognitive function participated either in the standard TTP of Berger [n = 35, age 67.6 +/- 8.9 years, diabetes duration 9.9 (0.04-35.4) years, HbA1c 10.3 +/- 2.0%] or in the specialized structured geriatric DICOF-TTP [n=33, age 70.4 +/- 8.2 years, diabetes duration 10.4 (0.03-24.9) years, HbA1c 10.7 +/- 1.8%]. RESULTS: After TTP there were no differences in knowledge and ability for diabetes self-management (standard/DICOF: knowledge 11.0 +/- 2.6 vs. 12.2 +/- 2.7 points, P = 0.11; handling 14.9 +/- 3.3 vs. 15.9 +/- 2.5 points, P = 0.18). However, patients who took part in the DICOF programme showed better scores in satisfaction with the education programme [standard/DICOF 44.7 (31-57) vs. 52.5 (45-59) points, P < 0.001]. Six months later the DICOF participants showed better results regarding diabetes self-management (standard/DICOF: handling 12.5 +/- 4.1 vs. 15.9 +/- 3.1 points, P = 0.001). Both groups showed HbA1c decrease (8.3 +/- 1.4 vs. 8.5 +/- 1.3%, P=0.62) and similar incidence of acute complications. CONCLUSIONS: Elderly patients with impaired cognitive function should take part in specialized structured TTP. This leads to both better satisfaction with the education programme and an improved ability for diabetes self-management. 相似文献
106.
目的研究IFN-γ,IL-4水平对血透患者外周血淋巴细胞(PBLC)凋亡调控蛋白Fas,Bcl-2表达的影响.方法采用流式细胞术的间接免疫荧光素标记法和双抗体夹心ELISA法,分别检测30例HD患者PBLC Fas,Bcl-2的表达水平和血清IFN-γ,IL-4水平.结果H-D患者血清IFN-γ水平明显低于健康对照组,IL-4浓度显著高于对照组(P均<0.01);其外周血PBLC的Fas表达水平明显高于健康对照组,而Bcl-2水平则明显低于健康对照组(P均<0.01).经相关分析发现:Fas表达水平与血清IFN-γ水平呈负相关,而与血清IL-4水平呈正相关(P均<0.01);Bcl-2表达水平与血清IFN-γ水平呈正相关,而与血清IL-4水平呈负相关(P均<0.01).结论HD患者PBLC存在异常凋亡现象;并与Th1型细胞因子分泌低下,以及TTh2型细胞因子分泌增加之间有一定的相关性,上述改变可能在HD患者的免疫功能紊乱中起着重要作用. 相似文献
107.
测定72例健康老年人(60-84岁)和65例健康青中年人(20-50岁)血清和尿β2微球蛋白(β2m),发现前血清β2m浓度比后明显增高(p<0.001);老年组≥70岁尿液β2m浓度也明显增高(p<0.05)。结果表明肾小球滤过率下降随年龄增长而降低,以后再出现肾小管功能减退。本试验较血清尿素氮、肌酐和内生肌酐清除率测定更为敏感。 相似文献
108.
SHILLA CHATTERJEE EUN SUNG PARK MELVYN S. SOLOFF 《International journal of urology》2004,11(10):876-884
BACKGROUND: Insulin-like growth factor binding protein-2 (IGFBP-2) is expressed by all human prostate cancer cell lines and dramatically increases in the serum of prostate cancer patients. However, the role of IGFBP-2 in prostatic tumorigenesis is not known. The aim of the present study was to investigate the effects of IGFBP-2 on the proliferation of DU145 human prostate cancer cells in culture. METHODS: Using cell proliferation assays, we examined the effects of exogenously administered and endogenously modulated levels of IGFBP-2 on the proliferation of DU145 cells. RESULT: Cell growth was stimulated by exogenously administered IGFBP-2, but significantly retarded (P < 0.05) by its neutralizing antibody. Overexpression of IGFBP-2 by transfection also stimulated cell growth, which was significantly (P < 0.05) inhibited in transfectants expressing antisense mRNA to IGFBP-2. Furthermore, the proliferation of IGFBP-2 overexpressing cells was significantly dampened by exogenously administered IGFBP-2 antibody. CONCLUSIONS: IGFBP-2 is an autocrine growth factor for DU145 human prostate cancer cells and cell proliferation can be significantly retarded by neutralizing or inhibiting its synthesis. These findings provide a strong rationale for targeting IGFBP-2 in the testing of novel strategies to treat prostate cancer. 相似文献
109.
K. F. Tait J. E. Collins J. M. Heward I. Eaves H. Snook J. A. Franklyn A. H. Barnett J. A. Todd M. Maranian A. Compston S. Sawcer S. C. L. Gough 《Diabetic medicine》2004,21(3):267-270
Aims The Type 1 diabetes susceptibility locus, IDDM2, has been mapped to a variable number of tandem repeats (VNTR) region 5′ upstream of the insulin (INS) and insulin‐like growth factor (IGF2) genes on chromosome 11p15. The function of the VNTR is uncertain; however, it may influence the thymic expression of the insulin gene and affect the development of immune self‐tolerance. The aim of this study was to investigate whether the INS VNTR region is a Type 1 diabetes‐specific locus or acting as a general autoimmunity gene. Methods We genotyped the INS‐IGF2 VNTR [using the surrogate INS?23 HphI single nucleotide polymorphism (SNP)] in 823 Graves’ disease (GD)/multiple sclerosis (MS) families, 1433 GD/MS patients and 837 healthy control subjects. Results We found no evidence of excess transmission of the allele associated with Type 1 diabetes to individuals affected by GD or MS within the families. Analysis of the case–control dataset showed no genotypic or allelic difference between the two populations. Conclusions These data suggest that the INS‐IGF2 VNTR is acting as a Type 1 diabetes‐specific susceptibility gene rather than as an influence on general autoimmunity. 相似文献
110.
A. Lecci F. Borsini L. Gragnani G. Volterra A. Meli 《Journal of neural transmission (Vienna, Austria : 1996)》1991,83(1-2):67-76
Summary Stress-induced hyperthermia (SIH), which is seen in the last mice removed from the cage, is a novel animal model sensitive to anxiolytic drugs. SIH is antagonized by CL 218872 (25 and 50 mg/kg, os), by tracazolate (5 and 7.5 mg/kg, ip) and by 2-AP-5 (50 and 100 mg/kg, ip). At higher dose, CL 218872 (100 mg/kg, os) and tracazolate (12.5 mg/kg, ip) lose their activity.PK 9084 (5–40 mg/kg, ip) and CGS 9896 (2–20 mg/kg, both ip and os) were also ineffective in preventing SIH. The anti-hyperthermic effect of CL 218872 (25 mg/kg) and tracazolate (7.5 mg/kg) was blocked by the benzodiazepine antagonist Ro 15–1788 (15 mg/kg). CGS 9896 (10 mg/kg, os) also reversed the effect of CL 218872 (25 mg/kg) on SIH.Differently from anxiolytics, MK-801 (0.5–1 mg/kg, os), PCP (2.5 mg/kg, ip) and d-amphetamine (10 mg/kg, ip) evoked hyperthermia in the first set of mice and prevented a further stress-induced rise of body temperature in the last set of mice. 相似文献