全文获取类型
收费全文 | 26049篇 |
免费 | 1227篇 |
国内免费 | 171篇 |
专业分类
耳鼻咽喉 | 148篇 |
儿科学 | 422篇 |
妇产科学 | 295篇 |
基础医学 | 2994篇 |
口腔科学 | 729篇 |
临床医学 | 1625篇 |
内科学 | 6532篇 |
皮肤病学 | 505篇 |
神经病学 | 2074篇 |
特种医学 | 1313篇 |
外科学 | 4655篇 |
综合类 | 113篇 |
一般理论 | 1篇 |
预防医学 | 874篇 |
眼科学 | 571篇 |
药学 | 1828篇 |
中国医学 | 30篇 |
肿瘤学 | 2738篇 |
出版年
2023年 | 116篇 |
2022年 | 261篇 |
2021年 | 446篇 |
2020年 | 278篇 |
2019年 | 379篇 |
2018年 | 447篇 |
2017年 | 337篇 |
2016年 | 428篇 |
2015年 | 419篇 |
2014年 | 537篇 |
2013年 | 712篇 |
2012年 | 1149篇 |
2011年 | 1326篇 |
2010年 | 774篇 |
2009年 | 649篇 |
2008年 | 1191篇 |
2007年 | 1353篇 |
2006年 | 1380篇 |
2005年 | 1327篇 |
2004年 | 1327篇 |
2003年 | 1252篇 |
2002年 | 1254篇 |
2001年 | 952篇 |
2000年 | 956篇 |
1999年 | 828篇 |
1998年 | 368篇 |
1997年 | 283篇 |
1996年 | 279篇 |
1995年 | 190篇 |
1994年 | 188篇 |
1993年 | 166篇 |
1992年 | 562篇 |
1991年 | 517篇 |
1990年 | 503篇 |
1989年 | 502篇 |
1988年 | 429篇 |
1987年 | 429篇 |
1986年 | 423篇 |
1985年 | 399篇 |
1984年 | 246篇 |
1983年 | 197篇 |
1982年 | 100篇 |
1979年 | 187篇 |
1978年 | 123篇 |
1977年 | 113篇 |
1975年 | 90篇 |
1973年 | 99篇 |
1972年 | 93篇 |
1970年 | 111篇 |
1969年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients
Masatoshi Ishibashi Seiichiro Morita Noriyoshi Umezaki Hisashi Ohtake 《European journal of nuclear medicine and molecular imaging》1988,14(1):25-27
The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using 99mTc-DTPA. The first renal peak count (the first Cmax; FCmax), time phase distribution (the first Tmax; FTmax), and blood velocity (the FCmax/FTmax) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FCmax and FCmax/FTmax images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically. 相似文献
52.
53.
S J Liu Q S Qu X P Xu Y T Liu S N Yin Y Takeuchi T Watanabe O Inoue M Yoshida M Ikeda 《American journal of industrial medicine》1992,22(3):313-323
A factory survey was conducted in three provinces in China from 1985 to 1989. The time-weighted average toluene concentrations in breathing zone air were monitored by diffusive sampling, whereas hippuric acid (HA) concentrations in shift-end urine samples were measured by high performance liquid chromatography (HPLC). Exposed workers (456 men and women) were those for whom toluene (up to 548 ppm toluene) accounted for greater than or equal to 90% of total exposure (by vapor concentration in ppm), whereas 517 nonexposed controls were recruited from the same factories or from factories of the same region. There was a linear correlation between the intensity of toluene exposure and HA concentration in the shift-end urine. Comparison of the results with findings in the literature shows that the toluene-induced increase in urinary HA concentration among workers in China is significantly smaller than the published values, whereas HA concentrations in urine samples from nonexposed controls are comparable to the levels previously reported. 相似文献
54.
N Inagaki K Yasuda G Inoue Y Okamoto H Yano Y Someya Y Ohmoto K Deguchi K Imagawa H Imura 《Diabetes》1992,41(5):592-597
To investigate the role of glucose in regulating glucose transporters in pancreatic beta-cells, we studied the hamster clonal beta-cell line HIT-T15, which retains responsiveness to glucose. Northern blot analysis demonstrates that GLUT2 and GLUT1 mRNA are abundant in HIT cells. After a 24-h culture with various concentrations of glucose (0-22.2 mM [0-400 mg/dl]), the GLUT2 mRNA level in HIT cells increased by 40% at 22.2 mM (400 mg/dl) glucose compared with 11.1 mM (200 mg/dl) without a change in mRNA stability. It also decreased proportionally to the reduction of glucose concentration. Glucose deprivation resulted in a decrease of GLUT2 mRNA to an almost undetectable level, with a marked increase in the degradation rate of mRNA. In contrast, the GLUT1 mRNA was not affected by glucose. We show that glucose uptake is highest in HIT cells incubated at 2.8-5.5 mM (50-99 mg/dl) glucose for 24 h, and that levels in cells cultured at 0 mM (0 mg/dl) and 22.2 mM (400 mg/dl) glucose decrease to approximately 20% of the maximum level. This decrease is consistent with the effects of glucose on glucose-stimulated insulin secretion in HIT cells. Our results indicate that glucose is involved in regulating GLUT2 mRNA and glucose uptake activity and that the glucose responsiveness of the insulin secretion correlates with the glucose-induced change in glucose uptake activity in HIT cells. 相似文献
55.
56.
A series of 1 beta-methylcarbapenem compounds, which have a 5'-substituted-N-methylpyrrolidin-3'-ylthio group as a C-2 side chain, have been prepared and their biological properties were investigated. Substitution with a methyl group on the nitrogen atom in the C-2 side chain effectively enhanced stability to renal dehydropeptidase-I as well as introduction of methylene spacer between the aminocarbonyl group and the pyrrolidine ring of the 5'-aminocarbonylpyrrolidin-3'-ylthio group. 相似文献
57.
M S Laskar M H Mahbub Kenjiro Yokoyama Masaiwa Inoue Noriaki Harada 《The European journal of contraception & reproductive health care》2006,11(3):220-227
OBJECTIVE: There might be a difference between non-working and working women in their perception of rights and privileges which may influence their contraceptive behavior. The purpose of this study was to examine contraceptive behavior among non-working and working women in Bangladesh determining associated factors. METHOD: Analysis was based on data from the 1999-2000 Bangladesh Demographic and Health Survey which employs nationally representative sample. RESULTS: The prevalence of current contraceptive use (any method) was 58.2% among non-working women and 65.5% among working women. Both rates are still low for the country. Some factors, such as discussed family planning with husband, husband approves family planning, desire for more children, and husband lives together, were influential determinants of lower contraceptive prevalence among the non-working women. CONCLUSION: The results indicate a necessity for social activities promoting husband-wife communication and women's participation in employment to enhance the use of contraceptives among Bangladeshi women, especially non-working women. 相似文献
58.
M. Shiraki M. Fukunaga K. Kushida H. Kishimoto Y. Taketani H. Minaguchi T. Inoue R. Morita H. Morii K. Yamamoto Y. Ohashi H. Orimo 《Osteoporosis international》2003,14(3):225-234
To determine the clinical recommended dosage regimen of risedronate for the treatment of involutional osteoporosis in Japanese patients, dose-response relationships for the efficacy and safety of this drug were investigated using a multi-center, randomized, double-blind, parallel group comparative design with four dose levels of risedronate (placebo, 1 mg, 2.5 mg and 5 mg per day). A total of 211 patients diagnosed with involutional osteoporosis according to the criteria proposed by the Japanese Society for Bone and Mineral Research were randomized and received one of the four doses once daily for 36 weeks. All patients were supplemented with 200 mg of calcium daily in the form of calcium lactate. The primary efficacy endpoint was the percent change in bone mineral density of the lumbar spine (L2-L4 BMD) determined by dual-energy X-ray absorptiometry (DXA) from baseline to the time of final evaluation. Changes in biochemical markers of bone turnover and safety profile were also compared. Percent changes in L2-L4 BMD at final evaluation in the placebo, and 1-, 2.5-, and 5-mg risedronate groups were 0.79+/-5.30, 2.71+/-4.93, 5.29+/-3.96, and 5.15+/-4.25% (mean+/-SD), respectively. A linear dose-response relationship was obtained up to a dose of 2.5 mg, whereas no further increase in BMD was observed at 5 mg. The decrease in bone turnover markers, including N-terminal osteocalcin, phosphorus, and urinary deoxypyridinoline, also showed a linear dose-response relationship up to a dose of 2.5 mg. Alkaline phosphatase level decreased linearly up to a dose of 5 mg. Risedronate was well tolerated in this 36-week study with 1- to 5-mg doses. Neither the overall incidence of adverse events nor the percentage of patients without problem in overall safety assessment differed significantly among the dose groups including the placebo group. Based on these results, a once-daily dose of 2.5 mg of risedronate, which is half that used in Caucasians, is recommended for the treatment of involutional osteoporosis in Japanese patients. 相似文献
59.
H. Shiozaki T. Kadowaki Y. Doki M. Inoue S. Tamura H. Oka T. Iwazawa S. Matsui K. Shimaya M. Takeichi et al. 《British journal of cancer》1995,71(2):250-258
Epidermal growth factor (EGF) mediates many pleiotrophic biological effects, one of which is alteration of cellular morphology. In the present study, we examine the possibility that this alteration in cell morphology is caused in part by the dysfunction of cadherin-mediated cell-cell adhesion using the human oesophageal cancer cell line TE-2R, which expresses E-cadherin and EGF receptor. In the presence of EGF, TE-2R changed its shape from round to fibroblastic and its colony formation from compact to sparse. Vanadate, a tyrosine phosphatase inhibitor, further potentiated the EGF response, whereas herbimycin A, a tyrosine kinase inhibitor, interfered with it. Moreover, EGF enabled the cells to invade in organotypic raft culture. These phenomena were accompanied not by decreased expression of the E-cadherin molecule but by a change in its localisation from the lateral adhesion site to the whole cell surface. Both alpha- and beta-catenin, cadherin-binding proteins, were also expressed at the same level throughout these morphological changes. Finally, we examined tyrosine phosphorylation of E-cadherin and alpha- and beta-catenin, and observed tyrosine phosphorylation of beta-catenin induced by EGF. These results suggest that EGF counteracts E-cadherin-mediated junctional assembly through phosphorylation of beta-catenin and modulates tumour cell behaviour to a more aggressive phenotype. 相似文献
60.
Silent cerebral lesions are increasingly found in mass screenings using MRI and magnetic resonance angiography (MRA). The purpose of this paper is to assess the usefulness of two non-invasive clinical tests-carotid ultrasound examination and brachial-ankle pulse wave velocity (baPWV) measurement-for predicting silent cerebral infarction (SCI) and silent intracranial arterial stenosis. Data were collected on 480 asymptomatic adult subjects who participated in a brain screening program at a single hospital between April 2003 and March 2006. All participants underwent baPWV measurement, B-mode ultrasonography of carotid arteries, MRI, and MRA. Data on 476 (99.1%) subjects were included in the analysis. Among these, 273 (57.4%) were male and the mean age was 51.5 years; 161 (33.8%) had carotid plaque; 33 (6.9%) had increased intima-media thickness (IMT); 99 (20.8%) had SCI; and 7 (1.5%) had intracranial arterial stenosis. The multivariate analysis showed that age (odds ratio [OR]: 1.12; 95% confidence interval [CI]: 1.08-1.17), carotid plaque (OR: 2.69; 1.59-4.56), increased IMT (OR: 2.40; 1.02-5.65), and a history of hypertension treatment (OR 2.22; 1.11-4.43) were significantly associated with SCI. Also, increased IMT (OR 9.70: 1.48-63.71) was related to intracranial arterial stenosis. Brachial-ankle PWV was related to SCI (p<0.01) and intracranial stenosis (p=0.01) in univariate analysis but not in multivariate analysis. The presence of carotid plaque and that of increased IMT on ultrasound examination are useful for assessing the risk of SIC. Increased IMT is also predictive of intracranial arterial stenosis. 相似文献