全文获取类型
收费全文 | 17050篇 |
免费 | 1016篇 |
国内免费 | 74篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 620篇 |
妇产科学 | 447篇 |
基础医学 | 2395篇 |
口腔科学 | 303篇 |
临床医学 | 1656篇 |
内科学 | 3667篇 |
皮肤病学 | 405篇 |
神经病学 | 1626篇 |
特种医学 | 395篇 |
外科学 | 1737篇 |
综合类 | 114篇 |
一般理论 | 16篇 |
预防医学 | 1445篇 |
眼科学 | 363篇 |
药学 | 1234篇 |
中国医学 | 25篇 |
肿瘤学 | 1580篇 |
出版年
2023年 | 168篇 |
2022年 | 298篇 |
2021年 | 551篇 |
2020年 | 322篇 |
2019年 | 446篇 |
2018年 | 519篇 |
2017年 | 405篇 |
2016年 | 423篇 |
2015年 | 500篇 |
2014年 | 673篇 |
2013年 | 860篇 |
2012年 | 1312篇 |
2011年 | 1267篇 |
2010年 | 748篇 |
2009年 | 627篇 |
2008年 | 1088篇 |
2007年 | 1112篇 |
2006年 | 1046篇 |
2005年 | 944篇 |
2004年 | 936篇 |
2003年 | 857篇 |
2002年 | 713篇 |
2001年 | 179篇 |
2000年 | 168篇 |
1999年 | 164篇 |
1998年 | 136篇 |
1997年 | 121篇 |
1996年 | 100篇 |
1995年 | 89篇 |
1994年 | 65篇 |
1993年 | 81篇 |
1992年 | 115篇 |
1991年 | 91篇 |
1990年 | 73篇 |
1989年 | 63篇 |
1988年 | 77篇 |
1987年 | 63篇 |
1986年 | 69篇 |
1985年 | 78篇 |
1984年 | 69篇 |
1983年 | 58篇 |
1982年 | 40篇 |
1981年 | 34篇 |
1980年 | 36篇 |
1979年 | 33篇 |
1978年 | 27篇 |
1977年 | 34篇 |
1976年 | 29篇 |
1975年 | 26篇 |
1972年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The effects of aerobic conditioning and/or caloric restriction in overweight men and women 总被引:1,自引:0,他引:1
The purpose of this study was to compare the effects of exercise and/or caloric restriction for 12 wk on body composition, maximal aerobic power (VO2max), and serum lipids and lipoproteins in overweight individuals. Forty-eight males and 48 females (means age = 36.6 yr), 120-140% of ideal body weight, were randomly assigned to groups (N = 12 each) of diet-exercise (DE), diet (D), exercise (E), and sedentary control (C). The dietary regimen consisted of 1,200 kcal X d-1, while exercise consisted of 5 d X wk-1 of 30 min of walk/running. For the males, body weight (BW) and fat weight loss in the DE group (-11.8 and 23%, respectively) were significantly greater than in the D group (-9.1 and -18%), with both groups significantly greater than for E and C. In the females, BW and fat weight loss for DE (-10.4 and -24%) were significantly greater than for D (-7.8 and -20%), with both groups significantly greater than E and C. Both DE and D males and females had a decrease in fat-free weight of -4.5 and -2.4%, respectively. In both sexes, the increase in VO2max-BW (ml X kg -1 X min-1) in DE (25%) was significantly greater than for E (15%), D (11%), and C (0%), with differences between E and D nonsignificant. However, increases in absolute VO2max (1 X min-1) and VO2max-fat-free weight (ml X kg-1 X min-1) were similar (P greater than 0.05) for DE and E (14%) but significantly greater compared to D and C (2%).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
42.
目前,人们正对乳腺磁共振成像(magnetic resonance imaging,MRI)的应用进行研究,表现在两个不同方面:一是将MRI列为乳腺癌高危妇女(例如BRCA1和BRCA2基因发生突变者)的筛查方法;二是对乳腺癌确诊或可疑患者行乳腺X线的同时辅以MRI以决定是否选用局部疗法。这两种用途的依据迥然不同。有预置性突变(predisposition mutations)的妇女乳腺癌发病年龄通常较低,此时由于乳腺组织较为致密,因而乳腺X线筛查的敏感性有所减低。 相似文献
43.
Lucia Carvalho Monica Lipay Francisco Belfort Ivan Santos Joyce Andrade Alessandra Haddad Flavia Brunstein Lydia Ferreira 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(9):961-968
BACKGROUND: Telomerase activity (TA) is believed to play a role in the regulation of senescence and to limit the number of cell divisions. The deregulation of telomerase appears to contribute to oncogenesis and the formation of immortal cell lines. As a result, it is believed that it could be used as a prognostic marker in melanoma. METHODS: TA was assayed by the polymerase chain reaction PCR-ELISA-based telomeric repeat amplification protocol (TRAP assay). One hundred and eight samples were distributed in four histological groups: 30 samples from primary cutaneous melanomas, 24 from peritumoural skin sites, 28 from benign melanocytic lesions, and 26 from normal skin sites as a control. RESULTS: TA was different among the four tested groups (Kruskall-Wallis test p<0.001), and increasing values of TA were observed progressing from normal skin to benign and then to malignant lesions. Among melanoma samples, there was a significant association between TA and ulceration (p=0.025), TA and vascular invasion (p=0.018) and TA and mitotic rate (p=0.029) (Mann-Whitney test). A linear regression analysis showed significant associations between the increase of TA with Breslow thickness (p=0.004) and the presence of satellites (p=0.002). CONCLUSIONS: We observed that TA had increased from control skin to peritumoural skin, and then to benign melanocytic lesions and finally to melanoma, suggesting tumour progression. TA showed higher values in the presence of some important histopathologic parameters related to poor prognosis in cutaneous melanoma such as ulceration, vascular invasion, satellites, high rates of mitosis, and in thicker tumours. 相似文献
44.
Monica J. Carson Tina V. Bilousova Shweta S. Puntambekar Benoit Melchior Jonathan M. Doose Iryna M. Ethell 《Neurotherapeutics》2007,4(4):571-579
Microglial activation and macrophage infiltration into the CNS are common features of CNS autoimmune disease and of chronic
neurodegenerative diseases. Because these cells largely express an overlapping set of common macrophage markers, it has been
difficult to separate their respective contributions to disease onset and progression. This problem is further confounded
by the many types of macrophages that have been termed microglia. Several approaches, ranging from molecular profiling of
isolated cells to the generation of irradiation chimeric rodent models, are now beginning to generate rudimentary definitions
distinguishing the various types of microglia and macrophages found within the CNS and the potential roles that these cells
may play in health and disease. 相似文献
45.
Julie N Hook Bruno Giordani David E Schteingart Kenneth Guire Jodie Giles Kelley Ryan Stephen S Gebarski Scott A Langenecker Monica N Starkman 《Journal of the International Neuropsychological Society》2007,13(1):21-29
Chronically elevated levels of cortisol have been associated with changes in cognitive functioning and brain morphology. Using Cushing's disease as a model to assess the effects of high levels of cortisol on cognitive functioning, 27 patients with Cushing's disease were examined at baseline and three successive follow-up periods up to 18 months after successful surgical treatment. At all follow-up periods, patients were administered cognitive tests as well as measures of plasma and urinary free cortisol. Structural MRIs and a depression measure were taken at baseline and one-year follow-up. Results showed that there is a specific pattern of significant cognitive and morphological improvement following successful treatment. Verbal fluency and recall showed recovery, although brief attention did not. Age of participants was a significant factor as to when recovery of function occurred; younger patients regained and sustained their improvement in cognitive functioning more quickly than older participants. Improvement in verbal recall also was associated with a decrease in cortisol levels as well as an increase in hippocampal formation volume one year after treatment. Overall, these findings suggest that at least some of the deleterious effects of prolonged hypercortisolemia on cognitive functioning are potentially reversible, up to at least 18 months post treatment. 相似文献
46.
P-A Krayenbuehl P Wiesli M Schmid C Schmid J A Ehses M Hersberger W Vetter G Schulthess 《Experimental and clinical endocrinology & diabetes》2007,115(5):322-326
BACKGROUND: Tumor necrosis factor (TNF)-alpha has pleiotropic effects in cytokine-mediated inflammation underlying atherogenesis. Activation of this inflammatory process is assumed to be different in diabetic and non-diabetic individuals. Previous studies in non-diabetic subjects showed no association between TNF-alpha -308G>A polymorphism and coronary artery disease. METHODS: Vascular complications and cytokine serum concentrations were assessed as a function of the TNF-alpha -308G>A polymorphism in 76 diabetic patients on low-dose aspirin. RESULTS: Of 76 adult diabetic patients, 18 (24%) carried the TNF-alpha -308A allele (17 AG, 1 AA) and 58 (76%) carried wild-type alleles (GG). Prevalence of macrovascular complications was 33% in TNF-alpha -308A allele carriers (AG+AA) and 78% in wild-type allele carriers (GG) (p<0.001). In contrast, prevalence of microvascular complications was 78% and 84%, respectively, and did not significantly differ between the study groups. TNF-alpha -308A allele carriers (AG+AA) compared to wild-type allele carriers (GG) had significantly lower median serum concentrations of hs-C-reactive protein (1.5 vs 2.9 mg/L, p=0.030), interleukin 1-beta (0.9 vs 1.2 ng/L, p=0.046), and interleukin-6 (3.6 vs 4.9 ng/L, p=0.023). In multiple regression analysis, the prevalence of macrovascular diabetic complications was significantly associated with TNF-alpha -308G>A polymorphism (p<0.001) and serum concentrations of HDL-cholesterol (p=0.007) while confounding effects of further variables were excluded. CONCLUSION: TNF-alpha -308G>A polymorphism modulates cytokine serum concentrations and macrovascular complications in diabetic patients on aspirin. Diabetic carriers of the TNF-alpha -308A allele might benefit more from a prophylaxis with low dose aspirin than non-carriers. 相似文献
47.
48.
Herbert Oelschlger Jiri Volke Michael Berthold Vetter Petra Nikolajewski 《Archiv der Pharmazie》1990,323(7):411-415
Loprazolam (1) is a tricyclic benzodiazepine containing a new butazadiene moiety, which has not been investigated by polarography up to now. 1 is reduced in three waves at a DME over the whole pH-region. In BRP (pH 2-9) 10 electrons are consumed in this process. The first step is suitable for the determination of 1 in Loprazolam tablets containing 1 or 2 mg. These tablets are on the pharmaceutical market in several European countries. The mechanism of the electrode process will be reported in the communication XXXIV. 相似文献
49.
50.