全文获取类型
收费全文 | 620篇 |
免费 | 42篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 15篇 |
妇产科学 | 9篇 |
基础医学 | 80篇 |
口腔科学 | 25篇 |
临床医学 | 54篇 |
内科学 | 164篇 |
皮肤病学 | 16篇 |
神经病学 | 68篇 |
特种医学 | 13篇 |
外科学 | 55篇 |
综合类 | 7篇 |
预防医学 | 23篇 |
眼科学 | 6篇 |
药学 | 68篇 |
肿瘤学 | 62篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 13篇 |
2019年 | 11篇 |
2018年 | 22篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 18篇 |
2014年 | 27篇 |
2013年 | 27篇 |
2012年 | 40篇 |
2011年 | 65篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 49篇 |
2007年 | 42篇 |
2006年 | 37篇 |
2005年 | 39篇 |
2004年 | 32篇 |
2003年 | 37篇 |
2002年 | 30篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有668条查询结果,搜索用时 265 毫秒
31.
Yotsutsuji T Saitoh O Suzuki M Hagino H Mori K Takahashi T Kurokawa K Matsui M Seto H Kurachi M 《Psychiatry research》2003,122(1):1-12
In vivo brain imaging and postmortem investigations have demonstrated ventricular enlargement in the brains of schizophrenic patients. However, the extent of changes in the volume of discrete ventricle subdivisions has not been clearly established. We conducted high-resolution three-dimensional magnetic resonance imaging in 40 schizophrenic patients (20 males and 20 females) and 40 healthy volunteers (20 males and 20 females). The lateral ventricle in each hemisphere was divided into the anterior horn, body, posterior horn and temporal horn. The volumes of the hemispheres, four subdivisions of the lateral ventricles and the third ventricle were measured. Compared to the control subjects, the bilateral hemisphere volumes were significantly lower in the patients than in the control subjects. In the lateral ventricular subdivisions of the male patients, the most substantial volume increase was in the left temporal horn, and volume increases were also observed in the bilateral anterior horns and the right body. The male patients also had a significantly increased volume of the third ventricle. The female patients showed similar patterns with less statistical significance. Thus, the schizophrenia patients showed ventricular enlargement, particularly in the left temporal horn, being more severely affected in the male than in the female. 相似文献
32.
Jee CD Lee HS Bae SI Yang HK Lee YM Rho MS Kim WH 《International journal of oncology》2005,26(5):1265-1271
The caspases are a family of aspartic acid-specific proteases that fulfill varied and often critical roles in mammalian apoptosis or in the proteolytic activation of cytokines. Caspase-1 (interleukin-1beta-converting enzyme) is a member of the cysteine protease family, which cleaves target proteins following aspartic acid residues. We investigated caspase-1 expression in stomach cancer, tissues and cell lines. Of 301 consecutive gastric carcinomas, 58 cases (19.3%) showed the expressional loss of caspase-1. Loss of caspase-1 expression was significantly associated with pTNM stage (p=0.03), lymph node metastasis (p=0.01) and patient survival (p<0.01). Caspase-1 expression was also significantly correlated in an inverse manner with p53 expression (p<0.01). Among the 11 gastric cancer cell lines examined, three cell lines showed loss of expression at the protein and mRNA levels. On treatment with 5-aza-2'-deoxycytidine (5-aza-C), and/or trichostatin A (TSA), all three cell lines re-expressed caspase-1 mRNA. The above findings suggest that epigenetic events such as DNA methylation and histone deacetylation play important roles in the regulation of caspase-1, and that loss of caspase-1 expression is associated with poor survival in gastric carcinoma. 相似文献
33.
Counting the dead and what they died from: an assessment of the global status of cause of death data 总被引:13,自引:0,他引:13
Mathers CD Fat DM Inoue M Rao C Lopez AD 《Bulletin of the World Health Organization》2005,83(3):171-177
OBJECTIVE: We sought to assess the current status of global data on death registration and to examine several indicators of data completeness and quality. METHODS: We summarized the availability of death registration data by year and country. Indicators of data quality were assessed for each country and included the timeliness, completeness and coverage of registration and the proportion of deaths assigned to ill-defined causes. FINDINGS: At the end of 2003 data on death registration were available from 115 countries, although they were essentially complete for only 64 countries. Coverage of death registration varies from close to 100% in the WHO European Region to less than 10% in the African Region. Only 23 countries have data that are more than 90% complete, where ill-defined causes account for less than 10% of total of causes of death, and where ICD-9 or ICD-10 codes are used. There are 28 countries where less than 70% of the data are complete or where ill-defined codes are assigned to more than 20% of deaths. Twelve high-income countries in western Europe are included among the 55 countries with intermediate-quality data. CONCLUSION: Few countries have good-quality data on mortality that can be used to adequately support policy development and implementation. There is an urgent need for countries to implement death registration systems, even if only through sample registration, or enhance their existing systems in order to rapidly improve knowledge about the most basic of health statistics: who dies from what? 相似文献
34.
35.
36.
Zhou SY Suzuki M Hagino H Takahashi T Kawasaki Y Matsui M Seto H Kurachi M 《Psychiatry research》2005,139(2):127-139
Methodological limitations in most previous magnetic resonance imaging (MRI)-based volumetric studies might have contributed to the inconsistent results regarding the frontal lobe regions of schizophrenia. Thus, applying the largest sample to date among those that have fully taken account of the intrinsic anatomical landmarks, this study aimed at clarifying the volumetric alterations of the frontal lobe and its subregions in schizophrenia. Participants comprised 59 patients with schizophrenia and 58 healthy controls. Measurements were performed on consecutive 1-mm-thick coronal slices reformatted from three-dimensional 1.5-T MR images. The whole frontal lobe was demarcated and then subdivided into the precentral gyrus (PCG), anterior cingulate, and posterior cingulate, and the remainder temporarily as the prefrontal region. Patients with schizophrenia had significant cortical volume reductions in the bilateral whole frontal lobe, prefrontal region, PCG, posterior cingulate, and right anterior cingulate. This study has confirmed that patients with schizophrenia do have cortical volume reductions in the whole frontal lobe and its subregions. Volume reduction in the PCG suggests that the primary motor cortex might contribute to the mechanisms of schizophrenia, considering its important role in the processing of multiple motor-related cognitive functioning suggested by the recent literature. 相似文献
37.
Okano Y Hase Y Kawajiri M Nishi Y Inui K Sakai N Tanaka Y Takatori K Kajiwara M Yamano T 《Pediatric research》2004,56(5):714-719
Tetrahydrobiopterin (BH4)-responsive phenylalanine hydroxylase (PAH) deficiency is characterized by reduction of blood phenylalanine level after a BH4-loading test. Most cases of BH4-responsive PAH deficiency include mild phenylketonuria (PKU) or mild hyperphenylalaninemia (HPA), but not all patients with mild PKU respond to BH4. We performed the phenylalanine breath test as reliable method to determine the BH4 responsiveness. Phenylalanine breath test quantitatively measures the conversion of L-[1-13C] phenylalanine to 13CO2 and is a noninvasive and rapid test. Twenty Japanese patients with HPA were examined with a dose of 10 mg/kg of 13C-phenylalanine with or without a dose of 10 mg . kg(-1) . d(-1) of BH4 for 3 d. The phenylalanine breath test [cumulative recovery rate (CRR)] could distinguish control subjects (15.4 +/- 1.5%); heterozygotes (10.3 +/- 1.0%); and mild HPA (2.74%), mild PKU (1.13 +/- 0.14%), and classical PKU patients (0.29 +/- 0.14%). The genotypes in mild PKU cases were compound heterozygotes with mild (L52S, R241C, R408Q) and severe mutations, whereas a mild HPA case was homozygote of R241C. CRR correlated inversely with pretreatment phenylalanine levels, indicating the gene dosage effects on PKU. BH4 loading increased CRR from 1.13 +/- 0.14 to 2.95 +/- 1.14% (2.6-fold) in mild PKU and from 2.74 to 7.22% (2.6-fold) in mild HPA. A CRR of 5 to 6% reflected maintenance of appropriate serum phenylalanine level. The phenylalanine breath test is useful for the diagnosis of BH4-responsive PAH deficiency and determination of the optimal dosage of BH4 without increasing blood phenylalanine level. 相似文献
38.
39.
To assess whether platelets are activated in transient global amnesia (TGA) and TIA, blood samples were analyzed by fluorescence-activated cytoscan using antibodies specific for platelet fibrinogen receptor (PAC1) and P-selectin (CD62P). Samples from TIA contained high levels of CD62P compared with age-matched control subjects, whereas those from TGA did not. The authors suggest that activated platelets are involved in brain ischemia, whereas ischemia appears not to be associated with most TGA. 相似文献
40.
BACKGROUND: To verify the hypothesis that isolated oligohydramnios in low-risk term or post-term pregnancy does not increase the risk of trauma to the fetus compared with a control group. METHODS: This prospective study compared a group of patients with low-risk pregnancy and oligohydramnios (AFI = or <50) and a control group which on ultrasonography performed 24 hours before delivery had an AFI volume >50 and = or <250 mm. The evaluation criteria included incidence of induction, modality of delivery and neonatal outcome. Statistical analysis was carried out using Student's "t"-test and the data set of categories was compared using the chi square test. RESULTS: From January 1997 to April 1999, 105 cases of oligohydramnios were compared with a control group (105 patients) matched for maternal age, gestation period and parity. The incidence of induction, fetal distress and variable deceleration was significantly higher in the group with AFI = or <50. The incidence of vacuum extractor, cesarean section, duration of labor and late deceleration did not differ between the two groups. No significant differences in neonatal outcome were found between the two groups. CONCLUSIONS: In patients with oligohydramnios without risk factors, the modality of delivery and neonatal outcome do not differ compared with those with normal amniotic fluid volume. 相似文献