全文获取类型
收费全文 | 860篇 |
免费 | 99篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 21篇 |
妇产科学 | 20篇 |
基础医学 | 114篇 |
口腔科学 | 28篇 |
临床医学 | 100篇 |
内科学 | 218篇 |
皮肤病学 | 46篇 |
神经病学 | 21篇 |
特种医学 | 193篇 |
外科学 | 37篇 |
综合类 | 14篇 |
预防医学 | 50篇 |
眼科学 | 1篇 |
药学 | 105篇 |
中国医学 | 1篇 |
肿瘤学 | 29篇 |
出版年
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 15篇 |
2014年 | 12篇 |
2013年 | 18篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 19篇 |
2009年 | 22篇 |
2008年 | 18篇 |
2007年 | 50篇 |
2006年 | 26篇 |
2005年 | 26篇 |
2004年 | 22篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 29篇 |
1998年 | 39篇 |
1997年 | 35篇 |
1996年 | 38篇 |
1995年 | 31篇 |
1994年 | 49篇 |
1993年 | 26篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 44篇 |
1988年 | 35篇 |
1987年 | 47篇 |
1986年 | 30篇 |
1985年 | 32篇 |
1984年 | 33篇 |
1983年 | 21篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1977年 | 7篇 |
1976年 | 19篇 |
1975年 | 19篇 |
1974年 | 10篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1970年 | 6篇 |
排序方式: 共有1003条查询结果,搜索用时 15 毫秒
21.
Interchromosomal duplications of the adrenoleukodystrophy locus: a phenomenon of pericentromeric plasticity 总被引:13,自引:5,他引:13
Eichler EE; Budarf ML; Rocchi M; Deaven LL; Doggett NA; Baldini A; Nelson DL; Mohrenweiser HW 《Human molecular genetics》1997,6(7):991-1002
A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD)
locus of the X chromosome has duplicated to specific locations near the
pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11.
Comparative sequence analysis reveals 92-96% nucleotide identity,
indicating that the autosomal ALD paralogs arose relatively recently during
the course of higher primate evolution (5-10 million years ago). Analysis
of sequences flanking the duplication region identifies the presence of an
unusual GCTTTTTGC repeat which may be a sequence-specific integration site
for the process of pericentromeric- directed transposition. The breakpoint
sequence and phylogenetic analysis predict a two-step transposition model,
in which a duplication from Xq28 to pericentromeric 2p11 occurred once,
followed by a rapid distribution of a larger duplicon cassette among the
pericentromeric regions. In addition to facilitating more effective
mutation detection among ALD patients, these findings provide further
insight into the molecular basis underlying a pericentromeric-directed
mechanism for non- homologous interchromosomal exchange.
相似文献
22.
Clinical aspects of pelvic inflammatory disease 总被引:2,自引:0,他引:2
Pelvic inflammatory disease (PID) is a common and poorly managed condition.
Untreated or inadequately treated, it leads to tubal infertility, ectopic
pregnancy and chronic pelvic pain. Diagnostic difficulties are compounded
by the wide variety of clinical presentations and the insensitivity and
poor specificity of laboratory tests. Better recognition of mild and
atypical disease needs a high index of suspicion whenever young, sexually
active women present with gynaecological symptoms. Laparoscopy supplemented
by microbiological tests and fimbrial minibiopsy should be regarded as the
diagnostic 'gold standard' for research studies; new studies are required
to identify techniques which might reduce under- and over-diagnosis. Early
treatment reduces the risk of an adverse effect on fertility. Any
therapeutic regimen selected should be effective against the common
aetiological agents Chlamydia trachomatis, Neisseria gonorrhoeae, genital
mycoplasmas and aerobic and anaerobic bacteria. Since at least 60% of cases
of PID can be attributed to infection with a sexually transmitted organism,
partner notification forms an essential part of management.
相似文献
23.
24.
Small intestinal lymphoma is a common feline tumour that most often develops in older cats, but also occurs in younger animals. In man, germline defects in the mismatch repair (MMR) genes most commonly cause hereditary non-polyposis colorectal cancer (HNPCC), or Lynch syndrome, while MMR defects have also been implicated in the development of lymphoid tumours in mice and in people. It was hypothesized that inherited MMR defects predispose a proportion of younger cats to the development of small intestinal lymphoma. MMR expression in 10 small intestinal lymphomas from younger cats (group 1, mean age 4.5 years) was compared with MMR expression in 30 small intestinal lymphomas from older cats (group 2, mean age 12.6 years). The cross-reactivity of the antibodies specific for the human MMR proteins MLH1, MSH2 and MSH6 with the corresponding proteins in feline tissues was first confirmed by western blotting. MMR expression was then investigated immunohistochemically in feline lymphomas. MLH1, MSH2 and MSH6 were detected immunohistochemically within neoplastic lymphocytes from all tumours examined. There were no significant differences between the two groups in either the intensity of immunolabelling or the percentage of neoplastic cells within which MMR proteins were detected. These results confirm the cross-reactivity of the human MMR antibodies with the corresponding proteins in feline tissues, but do not support the hypothesis that inherited germline MMR defects are a significant cause of feline small intestinal lymphomas. 相似文献
25.
Georgina L Ryland Sally M Hunter Maria A Doyle Simone M Rowley Michael Christie Prue E Allan David DL Bowtell Australian Ovarian Cancer Study Group Ian G Campbell 《The Journal of pathology》2013,229(3):469-476
Mucinous carcinomas represent a distinct morphological subtype which can arise from several organ sites, including the ovary, and their genetic characteristics are largely under‐described. Exome sequencing of 12 primary mucinous ovarian tumours identified RNF43 as the most frequently somatically mutated novel gene, secondary to KRAS and mutated at a frequency equal to that of TP53 and BRAF. Further screening of RNF43 in a larger cohort of ovarian tumours identified additional mutations, with a total frequency of 2/22 (9%) in mucinous ovarian borderline tumours and 6/29 (21%) in mucinous ovarian carcinomas. Seven mutations were predicted to truncate the protein and one missense mutation was predicted to be deleterious by in silico analysis. Six tumours had allelic imbalance at the RNF43 locus, with loss of the wild‐type allele. The mutation spectrum strongly suggests that RNF43 is an important tumour suppressor gene in mucinous ovarian tumours, similar to its reported role in mucinous pancreatic precancerous cysts. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
26.
Meeking DR Browne DL Allard S Munday J Chowienczyck PJ Shaw KM Cummings MH 《Diabetes care》2000,23(12):1840-1843
OBJECTIVE: Studies examining vasodilatory responses to acetylcholine (ACh) and its derivatives have been conflicting. Enhanced activation of the cyclo-oxygenase pathway and increased availability of vasodilatory prostanoids may occur in type 1 diabetes, and this may compensate for the observed reduction in nitric oxide (NO) activity We examined the role of cyclo-oxygenase inhibition on vasodilatory responses in 12 healthy normotensive type 1 diabetic adults and 12 nondiabetic control subjects of similar age, sex, and BMI. RESEARCH DESIGN AND METHODS: Forearm blood flow was measured using a venous occlusion plethysmography technique at baseline and after brachial artery infusions of ACh (7.5, 15, and 30 microg/min). Forearm blood flow at baseline and after ACh was then reexamined after local intra-arterial infusion of indomethacin (0.3 mg/100 ml forearm volume), a cyclo-oxygenase inhibitor. RESULTS: Baseline blood flow in the diabetic and control groups were similar (2.65 +/- 0.26 vs. 2.59 +/- 0.20 ml/min per 100 ml, respectively; P = 0.4). After indomethacin infusion, the vasodilatory responses to all doses of ACh were reduced in both the diabetic (by 25.30 +/- 4.90%) and control group (by 11.23 +/- 5.45%). However, the reduction in blood flow response to ACh after indomethacin was greater in diabetic patients compared with control subjects (P = 0.03). CONCLUSIONS: Our findings suggest that vasodilatory, prostanoids are important in determining endothelial response to ACh in diabetic and nondiabetic subjects. Increased prostaglandin-mediated vasodilation may compensate for attenuated responses to NO previously reported in diabetic subjects. These findings may partly explain the conflicting reports of endothelial dysfunction in patients with type 1 diabetes. 相似文献
27.
Little JD Munday J Lyall G Greene D Chubb G Orr M 《The Australian and New Zealand journal of psychiatry》2003,37(6):715-719
OBJECTIVE: To examine the clinical practice of right unilateral electroconvulsive therapy (ECT) administered at six times seizure threshold (6 x RUL ECT). METHOD: A retrospective review of all patients who received 6 x RUL ECT between July 2000 and June 2002. RESULTS: Twenty-one patients across a range of ages and diagnostic groups received D'Elia unilateral ECT at a seizure dosage at or above 388.8 milliCoumbs (mC). In order to sustain predetermined criteria for seizure adequacy, energy was increased in 71% of patients. Final seizure lengths of 45 s electroencephalographic (EEG) activity, 28 s motor activity (cuffed) and a post-ictal suppression index (PSI) of 83% were recorded. Eighty percent of patients responded after a mean of 7.0 treatments. Cognitive side-effects were noted in 21% of patients. Fifty-two percent relapsed on average 6.3 months after the last treatment despite continuation pharmacotherapy. CONCLUSIONS: 6 x RUL ECT was found to be clinically effective, associated with cognitive side-effects and relapse. The debate over electrode placement is likely to continue. 相似文献
28.
29.
DL DSouza SB Heinze RJ Dowling 《Journal of Medical Imaging and Radiation Oncology》2006,50(3):246-248
Lung cancer is not commonly known to metastasise to the perirenal space, with only five such cases previously published. We present an unusual case of perirenal lung metastases manifesting as diffuse perinephric stranding which to our knowledge has not been described before. 相似文献
30.
Brandon DL Marshall Thomas Kerr Chris Livingstone Kathy Li Julio SG Montaner Evan Wood 《Harm reduction journal》2008,5(1):35
Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less
is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth.
We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline,
15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection
(odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals
reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants
(p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved
Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention
among Aboriginal young people are urgently required. 相似文献