全文获取类型
收费全文 | 29049篇 |
免费 | 1394篇 |
国内免费 | 156篇 |
专业分类
耳鼻咽喉 | 211篇 |
儿科学 | 463篇 |
妇产科学 | 315篇 |
基础医学 | 3377篇 |
口腔科学 | 729篇 |
临床医学 | 1905篇 |
内科学 | 7056篇 |
皮肤病学 | 476篇 |
神经病学 | 2209篇 |
特种医学 | 1390篇 |
外科学 | 5512篇 |
综合类 | 121篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 920篇 |
眼科学 | 634篇 |
药学 | 2067篇 |
中国医学 | 32篇 |
肿瘤学 | 3180篇 |
出版年
2023年 | 130篇 |
2022年 | 298篇 |
2021年 | 513篇 |
2020年 | 321篇 |
2019年 | 422篇 |
2018年 | 522篇 |
2017年 | 418篇 |
2016年 | 545篇 |
2015年 | 536篇 |
2014年 | 668篇 |
2013年 | 883篇 |
2012年 | 1386篇 |
2011年 | 1563篇 |
2010年 | 911篇 |
2009年 | 797篇 |
2008年 | 1411篇 |
2007年 | 1570篇 |
2006年 | 1593篇 |
2005年 | 1530篇 |
2004年 | 1540篇 |
2003年 | 1361篇 |
2002年 | 1381篇 |
2001年 | 969篇 |
2000年 | 972篇 |
1999年 | 854篇 |
1998年 | 391篇 |
1997年 | 299篇 |
1996年 | 315篇 |
1995年 | 220篇 |
1994年 | 218篇 |
1993年 | 181篇 |
1992年 | 581篇 |
1991年 | 522篇 |
1990年 | 515篇 |
1989年 | 491篇 |
1988年 | 436篇 |
1987年 | 422篇 |
1986年 | 422篇 |
1985年 | 403篇 |
1984年 | 244篇 |
1983年 | 194篇 |
1982年 | 101篇 |
1979年 | 184篇 |
1978年 | 122篇 |
1977年 | 104篇 |
1975年 | 87篇 |
1973年 | 95篇 |
1972年 | 91篇 |
1970年 | 109篇 |
1969年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Makoto Kaneko Takuya Aoki Ryuichi Ohta Machiko Inoue Rakesh N. Modi 《Asia Pacific family medicine》2018,17(1):11
Background
As research in family medicine covers varied topics, multiple methodologies such as qualitative research (QR) and mixed methods research (MMR) are crucial. However, we do not know about the difference in the proportion of QR or MMR between Japan, the UK and the US. This knowledge is needed to shape future research within countries with developing primary care such as Japan and other Asian countries. This study aims to describe the use of QR and MMR in Japanese primary care and compare this to the UK and US; then to make informed recommendations for primary care research.Methods
A repeated cross-sectional study (2012–2016) based on the abstracts submitted to the annual conferences of the Japanese Primary Care Association in Japan, the Royal College of General Practitioners in the UK, and the North American Primary Care Research Group in the US and other North American countries. The proportions of QR/MMR among all the posters and paper presentations for each of these three conferences were assessed. Also examined were trends and types of qualitative techniques for all three countries and participants/settings for Japan.Results
There were 1080 abstracts for Japan, 575 for UK and 3614 for US conferences. QR/MMR proportions were 7.5%, 15.1% and 28.1%, respectively. Japan’s proportion was lower than that of UK and US (p?<?0.001). The proportion was increasing over time for the UK (p?=?0.02). Steps for coding and analyses was most popular for Japan, thematic analysis for the UK and grounded theory for the US. Primary care doctors and hospitals were the commonest contexts for Japan.Conclusions
QR and MMR were not as popular in primary care in Japan compared to the UK and the US, whereas their use was increasing in the UK. Approaches, participants and settings may differ among these countries. Education and promotion of QR/MMR and multi-disciplinary collaborations need to be recommended in Japan with developing primary care.992.
Tomohiro Numata Kaori Sato-Numata Yasunobu Okada Ryuji Inoue 《Journal of natural medicines》2018,72(3):694-705
Constipation is a common symptom frequently compromising the quality of daily life. Several mechanistically different drugs have been used to mitigate constipation, including Japanese herbal (Kampo) medicines. However, the mechanisms of their actions are often not well understood. Here we aimed to investigate the molecular mechanisms underlying the effects of Junchoto (JCT), a Kampo medicine empirically prescribed for chronic constipation. Cl? channel activity was measured by the patch-clamp method in human cystic fibrosis transmembrane conductance regulator (CFTR)-expressing HEK293T cells and human intestinal Caco-2 cells. cAMP was measured by a luciferase-based assay. Cell volume change was measured by a particle-sizing and particle-counting analyzer and video-microscopic measurement. In both CFTR-expressing HEK293T and Caco-2 cells, JCT dose-dependently induced whole-cell currents showing typical biophysical and pharmacological features of CFTR. Robust expression of CFTR was confirmed by RT-PCR and Western blotting in Caco-2 cells. Luciferase-based measurement revealed that JCT increases intracellular cAMP levels. Administration of the adenylate cyclase inhibitor SQ22536 or CFTR inhibitor-172, or treatment with small interfering RNAs (siRNA) targeting CFTR, abolished JCT-induced whole-cell currents, suggesting that elevated intracellular cAMP by JCT causes activation of CFTR in Caco-2 cells. Finally, blockade of CFTR activity by CFTR inhibitor-172 or siRNA-knockdown of CFTR or application of SQ22536 markedly reduced the degree of cell volume decrease induced by JCT. JCT can induce a Cl? efflux through the CFTR channel to promote water secretion, and this effect is likely mediated by increased cAMP production. 相似文献
993.
Shiori Otsuki Eiko Saito Norie Sawada Sarah K. Abe Akihisa Hidaka Taiki Yamaji Taichi Shimazu Atsushi Goto Motoki Iwasaki Hiroyasu Iso Tetsuya Mizoue Kenji Shibuya Manami Inoue Shoichiro Tsugane 《Annals of epidemiology》2018,28(9):597-604.e6
Purpose
We investigated the association between reproductive history and mortality from all and major causes among Japanese women.Methods
A large-scale population-based cohort study in Japan included 40,149 eligible women aged 40–69 years in 1990–1994. A total of 4788 deaths were reported during follow-up (average 20.9 years). A Cox proportional hazards regression model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (95% CI) for all-cause and major causes of mortality, adjusting for potential confounders.Results
Inverse associations with all-cause mortality were found in parous women (0.74 [0.67–0.82]), women with two or three births compared with a single birth (2 births: 0.88 [0.78–0.99]; 3 births: 0.83 [0.74–0.94]), parous women who breastfed (0.81 [0.75–0.87]), women who were older at menopause (0.88 [0.80–0.97]; p-trend: <0.01), and women who had a longer fertility span (0.85 [0.76–0.95]; p-trend: <0.01). A positive association was seen between all-cause mortality and later age at first birth (≥30 years) than early childbearing (≤22 years).Conclusions
Our study suggests that parous, two or three births, breastfeeding, late age at menopause, and longer reproductive span are associated with lower risk of all-cause of mortality. 相似文献994.
Nitrite reductase in Streptoccocus mutans plays a critical role in the survival of this pathogen in oral cavity 总被引:1,自引:0,他引:1
BACKGROUND/AIMS: The mechanisms of nitric oxide (NO) production by bacteria in the oral cavity are still not clearly defined but salivary streptococci have been reported to generate NO. The aim of this study was to clarify the mechanism of nitrite metabolism and generation of NO by Streptococcus mutans, a major pathogen of dental caries. METHODS: We searched the genomic database of oral pathogens for nitrite reductase and used a polymerase chain reaction (PCR) to clone the nirJ gene from S. mutans GS5. His-tagged recombinant NirJ protein was expressed in Escherichia coli BL21 and characterized. We constructed a nirJ gene-disrupted mutant strain of S. mutans (DeltanirJ) to analyze the physiological significance of nirJ. RESULTS: S. mutans generates NO from nitrite, probably as a result of the possession of nitrite reductase. We cloned the nirJ gene from S. mutans GS5 by PCR. The recombinant NirJ protein catalyzed the reduction of nitrite with a K(m) value of 3.37 microM and a specific activity of 2.5 micromol/min/mg of protein at 37 degrees C. Biochemical analysis revealed that the nitrite-reducing activity of the mutant (DeltanirJ) strain was significantly lower than that of the wild-type strain. The growth of the mutant strain, but not of the wild-type strain, was strongly suppressed by the presence of physiological levels of nitrite ( approximately 0.2 mM) in saliva. CONCLUSION: These observations suggest that the elimination of nitrite and/or the generation of NO are important for the survival of S. mutans in the oral cavity. 相似文献
995.
Takahashi N Kiyokawa K Rikimaru H Watanabe K Inoue Y 《The Journal of craniofacial surgery》2007,18(1):208-211
Congenital pharyngeal atresia is a very rare gastrointestinal anomaly, with only seven cases of complete pharyngeal atresia having been reported. Five of these cases were autopsy reports and success in surgery to enable oral ingestion was not reported even for the two surviving cases. This is a report of a 1.5-year-old boy with complete congenital pharyngeal atresia who was saved by an emergency tracheostomy directly after birth, and on whom we performed surgery to reconstruct the pharyngeal cavity and prevent re-occlusion and restonosis. Approximately four years after the surgery, no restenosis of the pharyngeal cavity has been observed, and the patient is capable of orally ingesting ordinary meals and breathing and vocalizing by closing the tracheal lumen for nearly satisfactory results. 相似文献
996.
Different localizations of drugs simultaneously administered in a strand of hair by micro‐segmental analysis
下载免费PDF全文
![点击此处可从《Drug testing and analysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kenji Kuwayama Hajime Miyaguchi Yuko T. Iwata Tatsuyuki Kanamori Kenji Tsujikawa Tadashi Yamamuro Hiroki Segawa Hiroyuki Inoue 《Drug testing and analysis》2018,10(4):750-760
Segmental hair analysis is used to estimate the time of drug intake at monthly precision in drug‐related crimes. Previously, we advanced this analytical method to specify the day of drug intake by cutting a strand of hair into 0.4‐mm segments, which correspond to daily hair growth. Herein, we investigated the distributions of 7 compounds in a strand of hair using micro‐segmental analysis. Several strands of hair were collected 33.1?229.4 days after subjects were administered 4 pharmaceutical products that contained 10 drugs in single doses within 32 hours. The administered drugs and resulting metabolites were extracted from 0.4‐mm hair segments and quantified using liquid chromatography–tandem mass spectrometry. Acidic and neutral compounds were detected at low amounts in any of the hair segments analyzed. Epinastine, fexofenadine, dihydrocodeine, chlorpheniramine, and the chlorpheniramine metabolite, desmethylchlorpheniramine each was localized to 2 regions within a strand of hair. By contrast, methylephedrine and its metabolite, ephedrine, each was localized to only a region. Among 20 individual strands of hair associated with different subjects and head regions, few differences in the shapes of drug concentration–hair segment curves for each compound were detected. Our data indicated that 2 mechanisms for drug uptake into hair can operate depending on drug properties and that co‐administered drugs can be localized to different regions in a strand of hair. Micro‐segmental analysis may aid in the identification of the day of drug intake and help to elucidate the mechanisms of drug uptake into hair. 相似文献
997.
998.
Shimizu Daisuke Miyazaki Dai Ehara Fumie Shimizu Yumiko Uotani Ryu Inata Koudai Sasaki Shin-ichi Inoue Yoshitsugu 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2020,258(1):157-166
Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the efficacy of real-time PCR for 16S ribosomal DNA (16S r-DNA) and sequencing for diagnosing microbial keratitis. We... 相似文献
999.
Kitajima Yoko Maruyama-Inoue Maiko Ito Arisa Sato Shimpei Inoue Tatsuya Yamane Shin Kadonosono Kazuaki 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2020,258(6):1279-1285
Graefe's Archive for Clinical and Experimental Ophthalmology - To identify the functional outcome and evaluate the morphologic changes of patients with pachychoroid neovasculopathy (PNV)... 相似文献
1000.
BACKGROUND AND STUDY AIMS: Palliative treatment for duodenal stenosis with an enteral stent is effective in enhancing the quality of life of patients with duodenal obstruction. There have been no thorough comparisons of duodenal stent placement with standard surgical gastrojejunostomy. The present study evaluated the outcome of duodenal stent placement and surgical gastrojejunostomy for palliation of duodenal stenosis caused by pancreaticobiliary malignancies. PATIENTS AND METHODS: Medical records for patients who underwent palliative enteral stenting during the past 9 years were retrospectively reviewed, and the patients' clinical outcome was compared with that in patients who underwent open surgical gastrojejunostomy during the same period. Patients who underwent prophylactic gastrojejunostomy were excluded from the study. RESULTS: Twenty patients (11 men, nine women; mean age 71.8 years) with pancreaticobiliary malignancy underwent palliative enteral stenting (stent group). Nineteen patients (12 men, seven women; mean age 68.7 years) with pancreaticobiliary malignancies underwent surgical gastrojejunostomy (bypass group). In the stent group, the diagnoses were 12 pancreatic cancers, six gallbladder cancers, one bile duct cancer, and one ampullary cancer. In the bypass group, the diagnoses were 14 pancreatic cancers and five gallbladder cancers. There were no significant differences between the two groups with regard to clinical background. Both procedures were successful. There were no differences between the two groups with regard to the technical or clinical success rates, patient survival, possibility of discharge, need for parenteral nutrition, or incidence of complications. However, the time from the procedure to resumption of food intake was shorter in the stent group than in the bypass group (1 day vs. 9 days; P < 0.0001). Improvement in the performance score after the procedure was observed more frequently in the stent group (65 % vs. 26.3 %; P < 0.05). In terms of the median hospital stay from the time of the procedure to the time of initial discharge home (12 patients vs. nine patients), there was no statistical difference (15 days vs. 30 days) due to the small size of the sample. There was no procedure-related mortality in either group. CONCLUSIONS: Palliative stent placement was more beneficial than surgical gastrojejunostomy in enhancing the quality of life of patients with duodenal obstruction due to pancreaticobiliary malignancies. 相似文献