全文获取类型
收费全文 | 1663858篇 |
免费 | 123441篇 |
国内免费 | 25713篇 |
专业分类
耳鼻咽喉 | 22748篇 |
儿科学 | 43888篇 |
妇产科学 | 43601篇 |
基础医学 | 227387篇 |
口腔科学 | 45492篇 |
临床医学 | 158147篇 |
内科学 | 312367篇 |
皮肤病学 | 33312篇 |
神经病学 | 125544篇 |
特种医学 | 65800篇 |
外国民族医学 | 650篇 |
外科学 | 241874篇 |
综合类 | 81189篇 |
现状与发展 | 82篇 |
一般理论 | 461篇 |
预防医学 | 112206篇 |
眼科学 | 41163篇 |
药学 | 133216篇 |
338篇 | |
中国医学 | 20414篇 |
肿瘤学 | 103133篇 |
出版年
2022年 | 16134篇 |
2021年 | 23618篇 |
2020年 | 16999篇 |
2019年 | 18743篇 |
2018年 | 23046篇 |
2017年 | 19479篇 |
2016年 | 19828篇 |
2015年 | 26148篇 |
2014年 | 34322篇 |
2013年 | 40618篇 |
2012年 | 55796篇 |
2011年 | 60592篇 |
2010年 | 36653篇 |
2009年 | 32472篇 |
2008年 | 50581篇 |
2007年 | 53738篇 |
2006年 | 54392篇 |
2005年 | 52875篇 |
2004年 | 45905篇 |
2003年 | 43978篇 |
2002年 | 42152篇 |
2001年 | 71111篇 |
2000年 | 73640篇 |
1999年 | 64465篇 |
1998年 | 20186篇 |
1997年 | 19001篇 |
1996年 | 17347篇 |
1995年 | 16222篇 |
1994年 | 14753篇 |
1992年 | 45777篇 |
1991年 | 43876篇 |
1990年 | 42876篇 |
1989年 | 41676篇 |
1988年 | 38805篇 |
1987年 | 37959篇 |
1986年 | 36257篇 |
1985年 | 34256篇 |
1984年 | 25512篇 |
1983年 | 21586篇 |
1979年 | 24254篇 |
1978年 | 17192篇 |
1977年 | 14966篇 |
1975年 | 15375篇 |
1974年 | 18229篇 |
1973年 | 17697篇 |
1972年 | 16949篇 |
1971年 | 15822篇 |
1970年 | 15024篇 |
1969年 | 14418篇 |
1968年 | 13545篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
BACKGROUND: Ankle brachial index(ABI)is widely involved in researches and clinical application of peripheral vascular injury of patients with diabetes (DM);however ,the application in cerebral infarction(CI)is rare.OBJECTIVE: To investigate the possible risk factor of cerebral infarction plus peripheral arterial disease(PAD),compare metabolic characteristics of patients who having CI plus PAD or only having CI,and understand the significance of ABI on screening and diagnosing CI plus PAD of lower limb.DESIGN: Contrast observation based on CI patients.SETTING: Deparment of Neurology,Nanxishan Hospital of Guangxi Zhang Autonomous Region.PARTICIPANTS:A total of 124 CI patients were selected from Department of Neurology.Nanxishan Hospital of Guangxi Zhuang Autonomous Region from July 2005 to April 2006,including 72 males and 52 females aged from 45 to 88 years.All patients met the diagnostic criteria of cerebrovascular disease established by National Academic Conference of Cerebrovascular Diseases in 1995 and determined as cerebral infarction with MRI or CT examination.All patients provided informed consent.There were 46 cases(37.2%)with CI plus PAD and 78 cases(62.8%)only with CI.METHODS: Blood pressure of bilateral ankles and upper extremities was measured at plain clinostatism with DINAMAP blood pressure monitor(GE Company).The ratio between average systolic pressure of lateral ankle and average systolic pressure of both upper extremities was regarded as ABI.The normal ABI was equal to or more than 0.9.If ABI<0.9 occurred at one side,patients were diagnosed as PAD.On the second morning after hospitalization,blood was collected to measure fasting blood glucose(FBG),2-hour postprandial blood glucose(PBG2h),glycosylated hemoglobin(HbAlc),triglycerides(TG),total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C).Among them,blood glucose.lipid and other biochemical markers were measured with enzyme chemistry assay and HbA1c was measured with HbA1c meter based on high liquid phase.Measurement data and enumeration data were compared with t test and Chi-square test.and multiple factors were deat with Logistic regression analysis and multivariate linear regression analysis.MAIN OUTCOME MEASURES: Results of correlation between ABI and metabolic markers with multivariate linear regression analysis;risk factors of CI plus PAD with Logistic regression analysis;comparisons of metabolic markers between PAD and non-PAD patients.RESULTS:All 124 patients with acute CI were involved in the final analysis.①Comparisons of metabolic markers:Levels of serum LDL-C and uric acid(UA)were higher of PAD patients than those of non-PAD patients(t=2.051 9,3.339 1,P<0.05);however,there were no significant differences among other metabolic markers(P>0.05).②Results of multivariate linear regression analysis:PBG2h,LDL.C and UA were obvious correlation with ABI of posterior tibial artery of lower limb and dorsal pedis artery rpartial regression coefficient:-0.231 to-1.010,P<0.05).③Risk factors of CI plus PAD with Logistic regression analysis:Age.Smoking history,sum of CI focus(≥3)and LDL-C were independent risk factor of CI plus PAD(OR=1.524-5.422,P<0.05-0.01 ).CONCLUSION:①Levels of serum LDL-C and UA of patients with CI plus PAD are high.②ABI of lower limbs is correlation with PBG2h,LDL-C and UA.In addition,measuring ABI is beneficial for early diagnosing PAD of lower limbs of patients who have poorly controlled blood glucose,abnormal lipid and poor renal function.③Age,LDL-C and sum of CI focus(≥3)are independent risk factors of CI plus PAD.It is of significance for screening non-PAD patients to evaluate risk degrees and prognosis and select therapeutic methods based on ABI measurement. 相似文献
52.
53.
54.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation. 相似文献
55.
Effects of poor glucose handling on arterial stiffness and left ventricular mass in normal children.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease. 相似文献
56.
57.
Setting goals to maintain hope. 总被引:3,自引:0,他引:3
58.
59.
60.
Daoyan Wei Henry Q. Xiong James L. Abbruzzese Keping Xie 《Journal of gastrointestinal cancer》2003,33(1):43-60
Pancreatic cancer is a lethal disease characterized by early metastasis, local invasion, and resistance to conventional therapies. To understand its etiology and eventually make prevention of it possible and effective, appropriate carcinogenesis models will certainly help us understand the effects of environmental and genetic elements on pancreatic carcinogenesis. The development of new treatment strategies to control cancer metastasis is of immediate urgency. Fulfillment of this task relies on our knowledge of the cellular and molecular biology of pancreatic cancer metastasis and the availability of biologically and clinically relevant model systems. Many of the existing pancreatic cancer carcinogenesis and metastasis animal models are described in this review. The advantages and disadvantages of each model and their clinical implications are discussed, and special attention is focused on experimental therapeutic strategies targeting pancreatic cancer metastasis. 相似文献