全文获取类型
收费全文 | 3274篇 |
免费 | 335篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 77篇 |
妇产科学 | 68篇 |
基础医学 | 490篇 |
口腔科学 | 134篇 |
临床医学 | 454篇 |
内科学 | 641篇 |
皮肤病学 | 48篇 |
神经病学 | 295篇 |
特种医学 | 87篇 |
外国民族医学 | 1篇 |
外科学 | 418篇 |
综合类 | 61篇 |
一般理论 | 1篇 |
预防医学 | 368篇 |
眼科学 | 26篇 |
药学 | 249篇 |
中国医学 | 6篇 |
肿瘤学 | 134篇 |
出版年
2022年 | 24篇 |
2021年 | 59篇 |
2019年 | 54篇 |
2018年 | 43篇 |
2017年 | 31篇 |
2016年 | 51篇 |
2015年 | 75篇 |
2014年 | 84篇 |
2013年 | 157篇 |
2012年 | 152篇 |
2011年 | 161篇 |
2010年 | 75篇 |
2009年 | 74篇 |
2008年 | 168篇 |
2007年 | 155篇 |
2006年 | 139篇 |
2005年 | 148篇 |
2004年 | 140篇 |
2003年 | 140篇 |
2002年 | 119篇 |
2001年 | 105篇 |
2000年 | 118篇 |
1999年 | 77篇 |
1998年 | 34篇 |
1997年 | 30篇 |
1996年 | 42篇 |
1995年 | 35篇 |
1994年 | 36篇 |
1993年 | 27篇 |
1992年 | 82篇 |
1991年 | 71篇 |
1990年 | 66篇 |
1989年 | 77篇 |
1988年 | 70篇 |
1987年 | 51篇 |
1986年 | 49篇 |
1985年 | 48篇 |
1984年 | 39篇 |
1983年 | 36篇 |
1982年 | 26篇 |
1979年 | 40篇 |
1978年 | 30篇 |
1977年 | 21篇 |
1974年 | 24篇 |
1973年 | 22篇 |
1972年 | 25篇 |
1971年 | 26篇 |
1970年 | 23篇 |
1969年 | 22篇 |
1968年 | 24篇 |
排序方式: 共有3614条查询结果,搜索用时 125 毫秒
1.
James A. Akingbasote Alison J. Foster Ian Wilson Sunil Sarda Huw B. Jones J. Gerry Kenna 《Archives of toxicology》2016,90(4):853-862
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment. 相似文献
2.
Donald B. Penzien PhD ; Frank Andrasik PhD ; Brian M. Freidenberg PhD ; Timothy T. Houle PhD ; Alvin E. Lake III PhD; Gay L. Lipchik PhD ; Kenneth A. Holroyd PhD ; Richard B. Lipton MD ; Douglas C. McCrory MD ; Justin M. Nash PhD ; Robert A. Nicholson PhD ; Scott W. Powers PhD ABPP ; Jeanetta C. Rains PhD ; David A. Wittrock PhD 《Headache》2005,45(S2):S110-S132
Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache. 相似文献
3.
M P Johnson X M Huang R Oberlender J F Nash D E Nichols 《European journal of pharmacology》1990,191(1):1-10
The present set of experiments was designed to examine the effects of extension of the alpha-methyl of p-chloroamphetamine (PCA) to an alpha-ethyl. Therefore, the alpha-ethyl homologue of PCA, 1-(4-chlorophenyl)-2-aminobutane (CAB), was compared to PCA in a number of pharmacological assays. CAB was 2-fold less potent than PCA at inhibiting synaptosomal uptake of [3H]5-hydroxytryptamine ([3H]5-HT), and 5-fold less potent at inhibiting uptake of [3H]dopamine ([3H]DA). In drug discrimination assays, CAB was approximately 3-fold less potent than PCA in animals trained to discriminate 3,4-methylenedioxymethamphetamine (MDMA) or its alpha-ethyl homologue, S-(+)-N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (S-(+)-MBDB), from saline. Monitoring with in vivo microdialysis, 10 mg/kg of PCA caused a large increase in extracellular DA and a significant decrease in 3,4-dihydroxyphenylacetic acid (DOPAC) in the striatum. In contrast, 11 mg/kg CAB caused no increase and 22 mg/kg CAB caused only a slight increase in extracellular DA. Both doses of CAB caused a decrease in extracellular DOPAC. The potential 5-HT neurotoxicity of CAB was examined by measuring monoamine and metabolite levels and [3H]paroxetine binding at one week following acute doses. A 10 mg/kg dose of PCA caused an 80% decrease in cortical and hippocampal serotonergic markers, while an equimolar dose of CAB decreased only hippocampal 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels. However, 22 mg/kg of CAB produced a 20-40% decrease in all serotonergic markers. Thus, extension of the alpha-alkyl significantly decreases the dopaminergic effects of PCA. The similar decrease in relative 5-HT neurotoxicity and the decreased ability to alter dopaminergic systems in vivo and in vitro supports the involvement of DA in the neurotoxicity of PCA. 相似文献
4.
Insulin resistance Type A and short 5th metacarpals. 总被引:1,自引:0,他引:1
BACKGROUND/AIMS: Insulin resistance is associated with a number genetic syndromes and a variety of defects of insulin action. METHODS: We describe three members of an extended family spanning two generations with insulin resistance Type A and short 5th metacarpals. The proband had secondary amenorrhoea, male pattern hair distribution, acne, hirsutism, deep voice, acanthosis nigricans, polycystic ovaries, diabetes, features of acromegaly, raised creatine kinase and triglyceride levels and short 5th metacarpals. Her growth hormone, adrenal steroid and testosterone levels were normal. The proband's daughter had severe acne, hirsutism, acanthosis nigricans, polycystic ovaries, raised triglyceride, glucose and testosterone level short metacarpals and normal insulin receptor gene. The proband's son had a muscular build, raised creatine kinase, hypertriglyceridaemia and short 5th metacarpals. His fasting insulin levels were normal but pro-insulin was raised. RESULT/CONCLUSION: There are many familial and genetic syndromes associated with insulin resistance. This family was diagnosed as having insulin resistance Type A. This family does not conform entirely to any of the previously described syndromes and a number of family members have the phenotype of short 5th metacarpals, which appears to be associated with the features of insulin resistance Type A. 相似文献
5.
6.
7.
A comparison of pharmacological (amitriptyline HCL) and nonpharmacological (cognitive-behavioral) therapies for chronic tension headaches 总被引:1,自引:0,他引:1
K A Holroyd J M Nash J D Pingel G E Cordingley A Jerome 《Journal of consulting and clinical psychology》1991,59(3):387-393
Forty-one recurrent tension headache sufferers were randomly assigned to either cognitive-behavioral therapy (administered in a primarily home-based treatment protocol) or to amitriptyline therapy (with dosage individualized at 25, 50, or 75 mg/day). Cognitive-behavioral therapy and amitriptyline each yielded clinically significant improvements in headache activity, both when improvement was assessed with patient daily recordings (56% and 27% reduction in headache index, respectively), and when improvement was assessed with neurologist ratings of clinical improvement (94% and 69% of patients rated at least moderately improved, respectively). In instances where differences in treatment effectiveness were observed (headache index, somatic complaints, perceptions of control of headache activity), cognitive-behavioral therapy yielded somewhat more positive outcomes than did amitriptyline. Neither treatment, however, eliminated headache problems. 相似文献
8.
Richard Sacknoff M.D. Robert A. Novelline M.D. James T. Rhea M.D. J. Nash Lawrason M.D. Patrick M. Rao M.D. 《Emergency radiology》1997,4(2):109-111
A 36-year-old man was brought to the emergency department after being assaulted. A mandible series showed a nondisplaced fracture through the angle of the mandible extending through the left third molar tooth. Axial slices from a nonhelical computed tomographic (CT) examination of the head as well as a helical CT examination of the mandible failed to demonstrate the fracture. The fracture was well shown, however, on sagittal CT reformations. Although CT is generally regarded as more sensitive than plain radiography for the detection of fractures, fractures may be overlooked by CT if examination in only one plane is performed. 相似文献
9.
10.
Value of grading squamous cell carcinoma of the head and neck. 总被引:3,自引:0,他引:3
We report a series of 3,294 patients with squamous cell carcinoma of the head and neck seen by one of us between 1963 and 1990. Two thousand and seven patients had a histologically proven and graded, but previously untreated, squamous cell carcinoma of the mucosal surfaces of the head and neck. These tumors had been graded previously by many different pathologists in many different hospitals, both in the United Kingdom and the United States, as well as continental Europe, over this period. Of the host factors both sex and age were associated with differentiation: 34% of patients less than age 50 had a well-differentiated tumor compared with 44% greater than age 50; 32% of women had a poorly differentiated tumor compared with 26% of men. General condition had no correlation with degree of differentiation. Site was closely associated with grading: well-differentiated tumors were more common in the mouth and larynx and poorly differentiated tumors in the pharynx. Furthermore, of poorly differentiated tumors, 19% arose from areas normally lined by keratinized squamous epithelium, 22% from a nonkeratinized area, 36% from respiratory epithelium, and 45% from areas normally covered by lymphoid epithelium. T stage had no significant correlation with differentiation. However, 46% of patients with poorly differentiated tumors had a nodal metastasis at presentation compared with only 28% of well-differentiated tumors. Distant metastases at presentation were found in 3.4% of poorly differentiated tumors compared with 1.8% of well-differentiated tumors. The survival fell significantly from 33% for well-differentiated tumors to 27% for poorly differentiated tumors. The recurrence rate at the primary site rose from 25% for well-differentiated tumors to 27% for poorly differentiated tumors, and recurrence in the lymph nodes rose from 26% to 30%. Both differences were just significant. 相似文献