全文获取类型
收费全文 | 2448623篇 |
免费 | 178031篇 |
国内免费 | 6475篇 |
专业分类
耳鼻咽喉 | 34299篇 |
儿科学 | 77229篇 |
妇产科学 | 68947篇 |
基础医学 | 352069篇 |
口腔科学 | 70403篇 |
临床医学 | 223594篇 |
内科学 | 472335篇 |
皮肤病学 | 52304篇 |
神经病学 | 199963篇 |
特种医学 | 92978篇 |
外国民族医学 | 782篇 |
外科学 | 359707篇 |
综合类 | 54882篇 |
现状与发展 | 7篇 |
一般理论 | 870篇 |
预防医学 | 191072篇 |
眼科学 | 56550篇 |
药学 | 183655篇 |
8篇 | |
中国医学 | 5556篇 |
肿瘤学 | 135919篇 |
出版年
2018年 | 25454篇 |
2017年 | 19757篇 |
2016年 | 21535篇 |
2015年 | 24556篇 |
2014年 | 34105篇 |
2013年 | 52648篇 |
2012年 | 70819篇 |
2011年 | 75011篇 |
2010年 | 44116篇 |
2009年 | 41552篇 |
2008年 | 70330篇 |
2007年 | 75436篇 |
2006年 | 75898篇 |
2005年 | 73482篇 |
2004年 | 70701篇 |
2003年 | 67865篇 |
2002年 | 66326篇 |
2001年 | 111565篇 |
2000年 | 115045篇 |
1999年 | 97218篇 |
1998年 | 26901篇 |
1997年 | 24476篇 |
1996年 | 23812篇 |
1995年 | 22511篇 |
1994年 | 21077篇 |
1993年 | 19653篇 |
1992年 | 76504篇 |
1991年 | 74581篇 |
1990年 | 72904篇 |
1989年 | 70187篇 |
1988年 | 65200篇 |
1987年 | 63967篇 |
1986年 | 61251篇 |
1985年 | 58266篇 |
1984年 | 43637篇 |
1983年 | 37302篇 |
1982年 | 22402篇 |
1981年 | 20120篇 |
1979年 | 41060篇 |
1978年 | 29344篇 |
1977年 | 24780篇 |
1976年 | 23351篇 |
1975年 | 25325篇 |
1974年 | 30430篇 |
1973年 | 29675篇 |
1972年 | 28024篇 |
1971年 | 26104篇 |
1970年 | 24570篇 |
1969年 | 23032篇 |
1968年 | 21809篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
901.
Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child 总被引:1,自引:0,他引:1
B. Wilken G. Helms H. J. Christen J. Bhnk J. Frahm F. Hanefeld 《Child's nervous system》1996,12(10):626-629
Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs. 相似文献
902.
903.
A prognosis of patients with a curative resected advanced cancer of the lower gastric region was worse than that of the other region of the stomach. The 5 year survival rate was only 47.3%. One of the main reasons was that a rate of lymph node recurrence was higher. In this point of view, we studied on lymphatic flow of the lower gastric region using an activated carbon particle (CH40). Lymph nodes were stained black soon after the injection of CH40 into the lower gastric wall at laparotomy. The black stained rate of an each regional lymph node was as follows. 3. 58%, 4. 17%, 5. 50%, 6. 25%, 1. 21%, 7. 58%, 8. 83%, 9. 58%, 11. 17% and 12. 33% in case of injection into the greater curvature and and 4. 31%, 6. 100%, 8. 25%, 9. 25%, 14V and 56% in case of injection into the lesser curvature. The stained rate was relatively high in 12 and 14V lymph node which we had not routinely dissected. The rates of lymph nodes stained black were related to those of cancer metastasis. The results suggest that lymphadenectomy of 12 for the cancer at the lesser curvature and that of 14V for the cancer at the greater curvature might make a prognosis of lower gastric cancer better. 相似文献
904.
905.
906.
Relation between energy expenditure and body composition in man: specific energy expenditure in vivo of fat and fat-free tissue 总被引:2,自引:0,他引:2
L Garby J S Garrow B J?rgensen O Lammert K Madsen P S?rensen J Webster 《European journal of clinical nutrition》1988,42(4):301-305
The relationship between energy expenditure and body composition, in terms of fat and fat-free masses, has previously been described by a variety of predictive regression equations with parameters devoid of physiological content. We present here results obtained by calculating the specific energy expenditure, ie, the energy expenditure per unit of mass, of fat and fat-free tissue on the basis of measurements of the total energy expenditure (EE), the masses of fat (FM), and fat-free (FFM) tissue using the following simple model: EE = k1.FM + k2.FFM where k1 and k2 are the specific energy expenditures of fat and fat-free tissue, respectively. The results of observations on 104 women at rest yielded values for k1 and k2 of 0.31 and 1.35 watts/kg of fat and fat-free mass, respectively, with standard errors of estimate of 0.074 and 0.052 watts/kg, respectively. Analysis of several series of measurements, from other sources and on smaller samples of subjects, yielded similar values at rest but with larger standard errors of estimate. Data from subjects performing varying amounts of work in 24-h measurements showed, as expected, larger values for both tissues. The results explain to a very large extent the well-established relation between resting metabolic rate and body weight, ie, a linear relation with a non-zero intercept. The results also offer a clear-cut explanation for the well known difference in energy expenditure between men and women with the same body weight. 相似文献
907.
K S Shiba K Kanamori H Cho N Furuhata T Harada A Shiba M Nakao 《Clinica chimica acta; international journal of clinical chemistry》1988,172(1):77-84
Proteins in normal human urine were clearly fractionated into 26 bands with molecular weights from 14,000 to 230,000 by means of one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with silver staining. The main band contained uromucoid, and the second main band had albumin. However, when urine samples from healthy persons were electrophoresed in the absence of SDS using polyacrylamide gel or agarose gel, or a cellulose acetate membrane, albumin but not uromucoid, frequently formed the main protein band. It is suggested that this is due to the complexing of uromucoid subunits to form a large molecule which cannot penetrate into the gel. In order to correctly fractionate all the proteins contained in normal human urine, it was concluded that it was best to treat a urine sample with SDS with pre-condensation, fractionate it by SDS-PAGE and stain fractionated proteins by a highly sensitive method such as silver staining. 相似文献
908.
Reevaluation of procarbazine for the treatment of recurrent malignant central nervous system tumors 总被引:1,自引:0,他引:1
Ninety-nine patients with primary recurrent malignant tumors of the central nervous system were treated with procarbazine as a single agent. Procarbazine was not given as a specified protocol, but for patients who were ineligible or refused other protocols. All patients had been treated previously with radiotherapy and 96 patients had also received previous chemotherapy. Twenty-five patients were treated at the first progression of their tumor, 47 were treated at the second progression, and 27 were treated at the third progression of their tumor. For the aggregate, the response plus stabilization rate was 27% for glioblastoma multiforme with median time to tumor progression of 30 weeks, and 28% for other anaplastic gliomas with a median time to tumor progression of 49 weeks. With respect to the percent of patients who responded or stabilized to treatment, these results are inferior to those reported previously for patients treated with procarbazine at recurrence. With respect to duration of response and stabilization, the data are comparable. 相似文献
909.
During recent decades there has been a controversial discussion if comparable plasma level profiles which are rather constant or those which show a high peak are more efficient for the cure of gonorrhoea. So far, investigations in this field were not based on the Grasso apparatus. Although the findings with cefotiam and ceftizoxime do not allow to formulate a general hypothesis without any restriction, it can be stated that on the basis of an identical area under the antibiotic level time curve, 'peak concentration' profiles are more favourable. 相似文献
910.
R. P. Heaney T. M. Zizic I. Fogelman W. P. Olszynski P. Geusens C. Kasibhatla N. Alsayed G. Isaia M. W. Davie C. H. Chesnut III 《Osteoporosis international》2002,13(6):501-505
Risedronate treatment reduces the risk of vertebral fracture in women with existing vertebral fractures, but its efficacy
in prevention of the first vertebral fracture in women with osteoporosis but without vertebral fractures has not been determined.
We examined the risk of first vertebral fracture in postmenopausal women who were enrolled in four placebo-controlled clinical
trials of risedronate and who had low lumbar spine bone mineral density (BMD) (mean T-score =–3.3) and no vertebral fractures at baseline. Subjects received risedronate 5 mg (n= 328) or placebo (n= 312) daily for up to 3 years; all subjects were given calcium (1000 mg daily), as well as vitamin D supplementation (up
to 500 IU daily) if baseline serum 25-hydroxyvitamin D levels were low. The incidence of first vertebral fracture was 9.4%
in the women treated with placebo and 2.6% in those treated with risedronate 5 mg (risk reduction of 75%, 95% confidence interval
37% to 90%; P= 0.002). The number of patients who would need to be treated to prevent one new vertebral fracture is 15. When subjects were
stratified by age, similar significant reductions were observed in patients with a mean age of 64 years (risk reduction of
70%, 95% CI 8% to 90%; P= 0.030) and in those with a mean age of 76 years (risk reduction of 80%, 95% CI 7% to 96%; P= 0.024). Risedronate treatment therefore significantly reduces the risk of first vertebral fracture in postmenopausal women
with osteoporosis, with a similar magnitude of effect early and late after the menopause.
Received: 12 September 2001 / Accepted: 11 December 2001 相似文献