全文获取类型
收费全文 | 94248篇 |
免费 | 8592篇 |
国内免费 | 2718篇 |
专业分类
耳鼻咽喉 | 1258篇 |
儿科学 | 1848篇 |
妇产科学 | 1510篇 |
基础医学 | 6386篇 |
口腔科学 | 2046篇 |
临床医学 | 14482篇 |
内科学 | 11425篇 |
皮肤病学 | 2526篇 |
神经病学 | 4844篇 |
特种医学 | 2242篇 |
外国民族医学 | 6篇 |
外科学 | 6076篇 |
综合类 | 12962篇 |
现状与发展 | 4篇 |
一般理论 | 3篇 |
预防医学 | 14534篇 |
眼科学 | 1281篇 |
药学 | 10975篇 |
265篇 | |
中国医学 | 6929篇 |
肿瘤学 | 3956篇 |
出版年
2024年 | 1171篇 |
2023年 | 2035篇 |
2022年 | 3180篇 |
2021年 | 4437篇 |
2020年 | 4408篇 |
2019年 | 3681篇 |
2018年 | 3460篇 |
2017年 | 3805篇 |
2016年 | 3697篇 |
2015年 | 3691篇 |
2014年 | 6622篇 |
2013年 | 7182篇 |
2012年 | 6098篇 |
2011年 | 6168篇 |
2010年 | 4852篇 |
2009年 | 4614篇 |
2008年 | 4639篇 |
2007年 | 4540篇 |
2006年 | 3973篇 |
2005年 | 3391篇 |
2004年 | 2795篇 |
2003年 | 2362篇 |
2002年 | 1896篇 |
2001年 | 1657篇 |
2000年 | 1333篇 |
1999年 | 1183篇 |
1998年 | 920篇 |
1997年 | 898篇 |
1996年 | 774篇 |
1995年 | 754篇 |
1994年 | 632篇 |
1993年 | 520篇 |
1992年 | 545篇 |
1991年 | 441篇 |
1990年 | 360篇 |
1989年 | 366篇 |
1988年 | 333篇 |
1987年 | 308篇 |
1986年 | 241篇 |
1985年 | 276篇 |
1984年 | 223篇 |
1983年 | 171篇 |
1982年 | 190篇 |
1981年 | 151篇 |
1980年 | 125篇 |
1979年 | 96篇 |
1978年 | 80篇 |
1977年 | 64篇 |
1976年 | 49篇 |
1975年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Eugene D. Barber 《Environmental and molecular mutagenesis》1994,23(3):228-233
Di(2-ethylhexyl) terephthalate (DEHT) is a commercially produced chemical (Kodaflex® DOTP) that is used as a general purpose, low-volatility plasticizer for polyvinyl chloride and other polymeric materials. Less than 30 million kilograms of DEHT are produced annually. DEHT is isomeric with di(2-ethylhexyl) phthalate (DEHP), a nongenotoxic rodent carcinogen whose mode of action has been suggested to derive from its ability to produce hepatocellular proliferation and/or hepatic peroxisome proliferation. Thus it is important to know the behavior of DEHT in genotoxicity assays in order to compare it with that of DEHP and other phthalate ester plasticizers. It is known from previously published studies that rats fed DEHT in the diet at 2,000 mg/kg produce urine that is negative in the Ames Salmonella bacterial mutagenicity assay in the presence and absence of induced rat liver S-9 and in the presence and obsence of β-glucuronidase/aryl sulfatase. Reported here are the results of direct testing of DEHT in the Ames plate incorporation assay, the Chinese hamster ovary/hypoxanthine guanine phosphoribosyl transferase (CHO/HGPRT) in vitro mammalian cell mutagenicity assay, and an in vitro chromosome aberrations assay using CHO cells. The results for mono(ethylhexyl) terephthalate (MEHT), a metabolite of DEHT, in the Ames Salmonella bacterial mutagenicity assay are also presented. All test results for both DEHT and MEHT were found to be negative, and it is therefore concluded that DEHT, like its isomeric relative DEHP, is not genotoxic. © 1994 Wiley-Liss, Inc. 相似文献
102.
ITSUGI NAGATOMO MD SYUNJI IWAGAWA MD MORIKUNI TAKIGAWA MD 《Psychiatry and clinical neurosciences》1997,51(2):53-56
Abstract We investigated factors correlated with abnormal behavior in the elderly residing in a special nursing home (group A) and a psychiatric hospital (group B) using the dementia behavior disturbance scale, the mini mental state examination, the Japanese version of the Philadelphia Geriatric Center morale scale, and the ADL assessment scale. The cognitive function of group B was decreased compared with that of group A, but most activities of daily living (ADL) in the latter group were disrupted compared with those in the former. Only a few categories of ADL correlated with abnormal behavior in group A, whereas cognitive function, quality of life, and most categories of ADL correlated with abnormal behavior in group B. These results suggest that factors correlated with abnormal behavior in the elderly differ within institutions of medical and social welfare systems. 相似文献
103.
Kalpana Agarwal Anita Mukherjee Archana Sharma Ramesh Sharma Kuldip Raj Bhardwaj Soumitra Sen 《Environmental and molecular mutagenesis》1992,19(4):323-326
Fenfluramine, an amphetamine derivative used in the treatment of obesity, has been evaluated in vivo in the bone marrow cells of Swiss albino mice using two cytogenetic endpoints for assessing its genotoxic and clastogenic potentials. Concentrations of 0.75, 1.5, 3.0, and 5.0 mg/kg b.w. were administered orally for the study of sister chromatid exchange frequencies and chromosome aberrations (CA). SCE frequencies showed a positive dose response; 1.5 mg/kg being the minimum effective concentration. Fen caused a prolongation of cell cycle at all concentrations. Except for the minimum therapeutic dose (0.75 mg), all other doses (1.5, 3.0, and 5.0 mg) showed a significant increase in the percentage of damaged cells over that of the vehicle control. The degree of clastogenicity was directly proportional to the dosage used and inversely related with the duration of treatment. A gradual reduction of the clastogenic potential was observed after 12 and 24 hr of exposure, indicating that the maximum effect occurs at the middle or late synthetic phase of the cell cycle. This study, probably the first detailed screening of the drug for its genotoxicity, shows that Fen is moderately clastogenic and a DNA damaging agent in vivo. 相似文献
104.
Met and unmet nursing care needs in men with prostate cancer. An explorative study. Part II 总被引:1,自引:0,他引:1
LISELOTTE JAKOBSSON RNT INGALILL RAHM HALLBERG RNT PhD & LARS LOVÉN MD PhD 《European journal of cancer care》1997,6(2):117-123
Men with prostate cancer ( n = 11) were interviewed during an in-patient period at a urological clinic, about their experiences of met and unmet needs from health professionals. Their perception of quality of life and sense of coherence were also assessed. The findings were analysed from a phenemenological-hermeneutic perspective and interpreted within the concept of transition. It was interpreted that objective functional health needs were mostly met by health professionals and subjective existential needs were mostly not met. The analysis revealed patients as passive or active receivers of care. Passive receivers were explicitly and implicitly stating unmet needs, or explicitly stating satisfaction with nursing care at the same time as implicitly contradicting, referring to their needs as bagatelles, unimportant, whereas active receivers talked about their needs explicitly with the staff and did not state implicit unmet needs. This suggests that nurses need to be aware of and have sensitive ears to undertones in statements and actively seek for patients' needs. The most important nursing care areas seemed to be to provide solutions to physical problems together with staff support including information, and acting to increase confidence in staff and staff availability. This encourages patients, wives and families, in co-operation, towards a healthy exit of transition. 相似文献
105.
目的:探讨直立倾斜试验(HUTT)对心脏神经症的诊断价值。方法:对59例心脏神经症患者,在排除器质性心脏病后行HUTT。结果:43例呈阳性,阳性发生率为72.9%。不同性别间反应类型有显著差异(P<0.05),女性多见血管抑制型(占76.9%)。不同反应类型间终末血压、心率有明显差异(P<0.05)。结论:HUTT可作为心脏神经症有效的辅助诊断方法。 相似文献
106.
Although tricyclic antidepressant are especially useful in the treatment of chronic pain conditions, most of the work about its mechanism of action has been made on acute pain tests. The present study was aimed at studying the role played by noradrenergic and opioidergic influences on the antinociceptive activity of subchronically administered clomipramine in the formalin test (a tonic pain model) in rats. Clomipramine produced antinociception after 7 days, administration (2.5 mg/kg/day), an effect equivalent to that obtained by acute morphine (5 mg/kg). The antinociceptive effect of clomipramine was inhibited by the following: nonspecific blocking of alpha1-and alpha2-adrenoceptors by phentolamine, specific blocking of alpha1-adrenoceptors by prazosin; stimulation of alpha2 receptors by clonidine; and blocking of the opioid receptors by naloxone. Blocking the alpha2-receptors with yohimbine did not antagonize the effect of clomipramine. These results suggest that clomipramine produces antinociception in this test, partly via the participation of the endogenous opioid system and partly by further activating or potentiating previously activated noradrenergic pathways which are involved in the control of pain information. 相似文献
107.
M V Shestakova N A Mukhin I I Dedov V N Titov V A Warshavsky 《Journal of internal medicine》1992,231(3):213-217
The acute effects of protein loading (1.5 g kg-1) on glomerular filtration rate (GFR) and urinary albumin excretion (UAE) were investigated in 23 type-I diabetic patients with no clinical nephropathy, and in 7 healthy subjects (controls). The results were compared with renal morphology data. In controls and in 14 diabetic patients (group 1) GFR increased by 27 and 37%, respectively, corresponding to normal renal reserve, but in 9 patients (group 2) GFR decreased by 20%, indicating the absence of a renal reserve. Microalbuminuria was found in none of the patients in group 1 and in 50% of patients in group 2. Two hours after the load UAE increased in all groups, but the increase was most marked in group 2, despite the fall in GFR. The two groups of patients did not differ with regard to the duration and control of diabetes, but differed markedly in terms of baseline GFR (131 vs. 195 ml min-1, P less than 0.01, in groups 1 and 2, respectively). Renal morphology showed minimal non-specific glomerular injury in group 1, and signs of glomerulosclerosis in group 2. We conclude that the impaired renal response to protein load precedes other subclinical manifestations of diabetic renal injury, and may be useful in the diagnosis of latent diabetic nephropathy. 相似文献
108.
本文采用中和试验、沉降反应和解离试验对135例已知血型人精液中ABH血型物质的分泌强度进行了检验,并将其分为强、中、弱三型。这对区别个人血型物质含量及性犯罪的法医学鉴定均有重要意义。并证明了AB型人精液中A、B血型物质含量不均等现象,并且绝大多数人B型物质高于A型物质。 相似文献
109.
110.
The cold pressor test: Vascular and myocardial response patterns and their stability 总被引:2,自引:0,他引:2
PATRICE G. SAAB MARIA M. LLABRE BARRY E. HURWITZ NEIL SCHNEIDERMAN WILLIAM WOHLGEMUTH LYNN A. DUREL CLIFFORD MASSIE JOACHIM NAGEL 《Psychophysiology》1993,30(4):366-373
The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases. Although the response panerns were generally similar across sites, exceptions were apparent for heart rate. Forehead stimulation was characterized by no significant change in heart rate, whereas limb (hand or foot) immersion was associated with significant heart rate acceleration. The responses elicited by the three cold pressor test conditions were reliable and showed little evidence of attenuation over the test-retest interval. 相似文献