全文获取类型
收费全文 | 205261篇 |
免费 | 16716篇 |
国内免费 | 7469篇 |
专业分类
耳鼻咽喉 | 1709篇 |
儿科学 | 2760篇 |
妇产科学 | 2340篇 |
基础医学 | 32289篇 |
口腔科学 | 3435篇 |
临床医学 | 15093篇 |
内科学 | 36812篇 |
皮肤病学 | 2945篇 |
神经病学 | 15225篇 |
特种医学 | 4283篇 |
外国民族医学 | 52篇 |
外科学 | 13837篇 |
综合类 | 27305篇 |
现状与发展 | 19篇 |
一般理论 | 6篇 |
预防医学 | 10160篇 |
眼科学 | 2018篇 |
药学 | 32577篇 |
45篇 | |
中国医学 | 8388篇 |
肿瘤学 | 18148篇 |
出版年
2024年 | 540篇 |
2023年 | 3873篇 |
2022年 | 8427篇 |
2021年 | 10253篇 |
2020年 | 7775篇 |
2019年 | 6540篇 |
2018年 | 6315篇 |
2017年 | 6420篇 |
2016年 | 6614篇 |
2015年 | 7747篇 |
2014年 | 12013篇 |
2013年 | 13361篇 |
2012年 | 11923篇 |
2011年 | 13714篇 |
2010年 | 11340篇 |
2009年 | 11543篇 |
2008年 | 11232篇 |
2007年 | 10233篇 |
2006年 | 9118篇 |
2005年 | 8045篇 |
2004年 | 6732篇 |
2003年 | 5940篇 |
2002年 | 4691篇 |
2001年 | 3803篇 |
2000年 | 3263篇 |
1999年 | 2916篇 |
1998年 | 2706篇 |
1997年 | 2552篇 |
1996年 | 2349篇 |
1995年 | 2070篇 |
1994年 | 1865篇 |
1993年 | 1613篇 |
1992年 | 1325篇 |
1991年 | 1247篇 |
1990年 | 1013篇 |
1989年 | 846篇 |
1988年 | 798篇 |
1987年 | 674篇 |
1986年 | 602篇 |
1985年 | 946篇 |
1984年 | 900篇 |
1983年 | 631篇 |
1982年 | 640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
61.
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
62.
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
63.
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
64.
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
65.
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
66.
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
67.
袁柳明 《浙江中西医结合杂志》2007,17(1):35-36
我院自2001年1月-2005年12月,在常规综合治疗的基础上采用中药合654-2治疗重度黄疸型肝炎42例,疗效较满意,报道如下。 相似文献
68.
Gary Coleman Tom A. Gardiner Ariel Boutaud Alan W. Stitt 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2007,245(4):581-587
Background A recombinant form of the α2(IV)NC1 domain of type IV collagen has been shown to have potent anti-angiogenic activity although
this peptide has not been studied in the context of proliferative retinopathies. In the current investigation we examined
the potential for α2(IV)NC1 to regulate retinal microvascular endothelial cell function using a range of in vitro and in vivo
assay systems.
Materials and methods α2(IV)NC1 at concentrations between 0.1 and 1 μg/ml was added to retinal microvascular endothelial cells (RMECs) followed
by assessment of cell attachment, proliferation and survival. This agent was also tested within a novel in vitro three-dimensional
retinal angiogenesis assay and the number of angiogenic sprouts quantified. α2(IV)NC1 was also delivered intra-vitreally to
mice with oxygen-induced proliferative retinopathy (OIR) and neovascularisation evaluated in comparison with vehicle-treated
controls.
Results RMECs treated with α2(IV)NC1 (0.1, 0.5 and 1 μg/ml) showed delayed attachment at 3 h post-seeding, although this deficit had
been restored at the 6-h time point. BrdU assay of DNA replication revealed that confluent RMECs treated with α2(IV)NC1 showed
no measurable response in comparison with vehicle-treated controls. By contrast, proliferation of sub-confluent RMECs was
significantly reduced by α2(IV)NC1 at 0.5 μg/ml (P<0.01). α2(IV)NC1 also induced apoptosis in RMECs and inhibited angiogenesis of pre-existing retinal vascular networks in
vitro (P<0.001). Intra-vitreal injection of α2(IV)NC1 in the OIR model significantly inhibited pre-retinal neovascularisation compared
with vehicle-treated controls (P<0.001).
Conclusion α2(IV)NC1 inhibits angiogenesis in the retinal microvasculature. This recombinant protein has potential for the treatment
of neovascularisation in proliferative retinopathies.
BioStratum Inc. did not sponsor this research in any way. None of the authors are paid consultants with this company. 相似文献
69.
Klein [Klein, A. S. (2006). Separating transducer nonlinearities and multiplicative noise in contrast discrimination. Vision Research, 46, 4279-4293] questions the existence of intrinsic singularities in two-alternative force-choice (2AFC) Signal Detection Theory (SDT) models, suggesting that the singularities found in Katkov et al. [Katkov, M., Tsodyks, M., & Sagi, D. (2006a). Singularities in the inverse modeling of 2AFC contrast discrimination data. Vision Research, 46, 259-266; Katkov, M., Tsodyks, M., & Sagi, D. (2006b). Analysis of two-alternative force-choice Signal Detection Theory model. Journal of Mathematical Psychology, 50, 411-420] are due to discarding higher order terms in the Taylor expansion of d' and/or limited to steep psychometric functions. Here we provide some simple intuitive examples that illustrate the results described in Katkov et al. (2006a, 2006b). We show, for the constant noise model, that singularities exist when exact values of d' are computed and that the singularities are not limited to steep psychometric functions. In these cases the disambiguation of the different models requires millions of trials. 相似文献
70.
Introduction Hypothalamic hamartomas are congenital malformations. Clinically, they can be asymptomatic, but they cause seizures, mental
retardation and precocious puberty in many cases.
Case report A 20-day-old boy with hypothalamic hamartoma and bilateral anophthalmia was presented. Except those, no other congenital anomaly
was detected.
Conclusion This is a rare case of hypothalamic hamartoma with bilateral anophthalmia. The mutations at SOX2 has an important role in
the developing brain and eyes. 相似文献