全文获取类型
收费全文 | 46194篇 |
免费 | 2172篇 |
国内免费 | 381篇 |
专业分类
耳鼻咽喉 | 475篇 |
儿科学 | 975篇 |
妇产科学 | 501篇 |
基础医学 | 6116篇 |
口腔科学 | 797篇 |
临床医学 | 2751篇 |
内科学 | 12038篇 |
皮肤病学 | 1301篇 |
神经病学 | 3348篇 |
特种医学 | 1829篇 |
外科学 | 7901篇 |
综合类 | 185篇 |
一般理论 | 6篇 |
预防医学 | 1257篇 |
眼科学 | 1012篇 |
药学 | 2831篇 |
中国医学 | 184篇 |
肿瘤学 | 5240篇 |
出版年
2023年 | 248篇 |
2022年 | 513篇 |
2021年 | 912篇 |
2020年 | 476篇 |
2019年 | 669篇 |
2018年 | 939篇 |
2017年 | 720篇 |
2016年 | 904篇 |
2015年 | 978篇 |
2014年 | 1277篇 |
2013年 | 1632篇 |
2012年 | 2619篇 |
2011年 | 2924篇 |
2010年 | 1653篇 |
2009年 | 1527篇 |
2008年 | 2764篇 |
2007年 | 2989篇 |
2006年 | 3013篇 |
2005年 | 3039篇 |
2004年 | 3140篇 |
2003年 | 3202篇 |
2002年 | 3163篇 |
2001年 | 584篇 |
2000年 | 514篇 |
1999年 | 654篇 |
1998年 | 808篇 |
1997年 | 668篇 |
1996年 | 639篇 |
1995年 | 532篇 |
1994年 | 476篇 |
1993年 | 512篇 |
1992年 | 380篇 |
1991年 | 375篇 |
1990年 | 334篇 |
1989年 | 286篇 |
1988年 | 295篇 |
1987年 | 250篇 |
1986年 | 187篇 |
1985年 | 195篇 |
1984年 | 205篇 |
1983年 | 156篇 |
1982年 | 134篇 |
1981年 | 175篇 |
1980年 | 147篇 |
1979年 | 112篇 |
1978年 | 118篇 |
1977年 | 93篇 |
1976年 | 70篇 |
1975年 | 72篇 |
1974年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
Makoto Sekiguchi Hiroshi Hoshizaki Hitoshi Adachi Shigeru Ohshima Koichi Taniguchi Masahiko Kurabayashi 《Circulation journal》2004,68(7):610-614
BACKGROUND: A prospective randomized study compared the preventive effects of ticlopidine plus aspirin therapy versus cilostazol plus aspirin therapy on subacute thrombosis (SAT) and restenosis after coronary stenting. METHODS AND RESULTS: After successful stenting of 327 coronary lesions in 282 consecutive patients, the patients were randomized to receive ticlopidine (200 mg/day) or cilostazol (200 mg/day). Aspirin (81 mg/day) was administered concomitantly in both groups. SAT occurred in 1 patient in the ticlopidine group (0.7%) and in 8 patients in the cilostazol group (5.6%, p=0.037). Based on follow-up angiography, restenosis occurred in 30 patients (23.3%) in the ticlopidine group and 35 patients (26.9%) in the cilostazol group (NS). The late loss was significantly smaller in the cilostazol group than the ticlopidine group (1.08+/-0.95 mm vs 0.78+/-0.93 mm, respectively, p=0.037). No significant differences between the 2 groups were observed with respect to the rates of total death, non-fatal cardiovascular events, or bleeding complications. CONCLUSION: The ticlopidine group showed significantly less SAT after stenting compared with the cilostazol group. After 6 months of treatment, the inhibition of neointimal proliferation was greater in the cilostazol group than in the ticlopidine group, but the prevention of restenosis was not confirmed. 相似文献
962.
John P. Marenco Hiroshi Nakagawa Shawn Yang David MacAdam Lucien Xu Ding S. He Mark S. Link Munther K. Homoud N.A. Mark Estes III Paul J. Wang 《Annals of noninvasive electrocardiology》2003,8(1):55-59
Background: Identifying the timing and morphology of an ectopic P wave from the surface electrogram can aid in the diagnosis and localization of atrial arrhythmias. Given the relatively short coupling interval of atrial ectopic beats, the P wave is often obscured by the larger amplitude QRS‐T wave complex. A method to uncover such “buried” P waves using a standard 12‐lead surface ECG would be clinically useful and could potentially be a noninvasive guide to catheter ablation of focal atrial tachycardia. Methods: We developed an automated computerized program (BARD DUO LAB SYSTEM?) designed to subtract the QRS‐T wave complex from the surface electrogram and uncover a previously obscured P wave. The purpose of the present study was to validate this program. The surface ECG from 21 patients undergoing atrial pacing during electrophysiologic study (group I) and 10 patients with atrial tachycardia (group II) were analyzed and the derived P‐wave morphology assessed using correlation waveform analysis (CWA) and visual grading by three reviewers. Results: The algorithm successfully uncovered the P wave in each surface ECG. For the 21 patients in group I, average CWA comparing the derived P wave with the previous paced P wave was 83%. Average CWA for group II was 82%. Visual grading of the match between derived P waves and paced P waves revealed a 21/21 match in group I patients and a 12/12 match in 9/10 of group II patients. Conclusions: An ectopic atrial P wave obscured by a coincident QRS‐T wave complex can be accurately uncovered using this new algorithm. Addition of this technique to existing methods may improve the diagnosis of atrial arrhythmias and aid in the localization and ablation of ectopic atrial foci. 相似文献
963.
Hiroshi Ishii Kenji Kishi Hisako Kushima Kazuhiko Hashinaga Kenji Umeki Minoru Ohama Issei Tokimatsu Kazufumi Hiramatsu Jun-Ichi Kadota 《Nihon Kokyūki Gakkai zasshi》2007,45(6):483-488
We report a rare case of pulmonary lymphomatoid granulomatosis radiologically mimicking interstitial pneumonia. A 57-year-old man was admitted to our hospital because of chest bilateral reticular shadow with sustained cough and breathlessness for 10 years. Chest CT scans showed multiple ground-glass opacities, traction bronchiectasis and cystic change in both lungs, in addition to hilar and mediastinal lymphadenopathy. A histopathologically diagnosis of pulmonary lymphomatoid granulomatosis (angiocentric immunoproliferative lesion, grade 1) was made by thoracoscopic lung biopsy. In this case, serological and immunohistochemical analyses did not show Epstein-Barr virus infection. No clinical or radiological deterioration has been observed thereafter despite no medication. 相似文献
964.
965.
Ohuchi H Kato M Asano H Tanabe H Ogiwara M Imanaka K Gojo S Yokote Y Kyo S 《Asian cardiovascular & thoracic annals》2003,11(3):233-236
The purpose of this paper was to assess the results and feasibility of simultaneous coronary artery bypass grafting and abdominal aortic aneurysm repair. Twenty nine patients with a mean age of 65 years underwent simultaneous coronary artery bypass grafting and abdominal aortic aneurysm repair between June 1990 and March 2002. All patients had significant coronary artery disease and were considered as indicated for coronary artery bypass grafting. This was performed first in 28 patients and simultaneously with abdominal aortic aneurysm repair in one, with a mean number of grafts of 2.5, a mean aortic cross-clamp time of 40 minutes, and a mean bypass time of 115 minutes. Eight straight and 21 bifurcated grafts were employed. The total operating time averaged 400 minutes. The median postoperative hospital stay was 18 days. One patient died of stroke and mediastinitis, for a mortality rate of 3.5%. This experience suggests that combined coronary artery bypass grafting and abdominal aortic aneurysm repair is both safe and effective. 相似文献
966.
The prevalence of immunity against diphtheria among Okayama local government staff members involved in diphtheria infection control was measured. Diphtheria booster vaccination was administered to staff members with low antitoxin levels (<0.1 IU/ml) in order to reinforce of immunity. Ninety-one (36.7%) of 248 staff members, 20-69 years of age, had fully protective antitoxin levels (> or =0.1 IU/ml), and the remaining 157 (63.3%) showed levels of <0.1 IU/ml. The rate of full protection was higher in females (44.9%) than in males (22.8%) and was also higher in the diphtheria-pertussis mixed vaccine (born in 1958-1967) and diphtheria-pertussis-tetanus mixed vaccine (born in 1968-) (58.3-61.0%) groups than in diphtheria vaccine (born in 1948-1957) and non-vaccinated (born until 1947) (7.4-18.9%) groups. Though antitoxin levels of 13 (68.4%) out of 19 staff members given booster vaccinations increased to 0.1 IU/ml, 50% of these individuals then showed levels of <0.1 IU/ml after 3 years. Most of the staff members with antitoxin levels of > or =0.1 IU/ml in the non-booster vaccination group maintained their immunity levels for 2-4 years, independent of their history of vaccination. To ensure that staff members of the local government have fully protective antitoxin levels against diphtheria, periodical confirmation of antitoxin levels and booster vaccination should both be systematically carried out. 相似文献
967.
Growth factors essential for self-renewal and expansion of mouse spermatogonial stem cells 总被引:37,自引:0,他引:37
Kubota H Avarbock MR Brinster RL 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(47):16489-16494
Spermatogonial stem cells (SSCs) self-renew and produce large numbers of committed progenitors that are destined to differentiate into spermatozoa throughout life. However, the growth factors essential for self-renewal of SSCs remain unclear. In this study, a serum-free culture system and a transplantation assay for SSCs were used to identify exogenous soluble factors that promote proliferation of SSCs. Mouse pup testis cells were enriched for SSCs by selection with an anti-Thy-1 antibody and cultured on STO (SIM mouse embryo-derived thioguanine and ouabain resistant) feeders in a serum-free defined medium. In the presence of glial cell line-derived neurotrophic factor (GDNF), SSCs from DBA/2J strain mice formed densely packed clumps of cells and continuously proliferated. However, other strains of mice required the addition of soluble GDNF-family receptor alpha-1 and basic fibroblast growth factor to support replication. The functional transplantation assay proved that the clump-forming cells are indeed SSCs. Thus, GDNF-induced cell signaling plays a central role in SSC self-renewal. The number of SSCs in culture doubled every 5.6 days, and the clump-forming cells strongly expressed Oct-4. Under these conditions, SSCs proliferated over 6 months, reconstituted long-term spermatogenesis after transplantation into recipient testes, and restored fertility to infertile recipients. The identification of exogenous factors that allow continuous proliferation of SSCs in vitro establishes the foundation to study the basic biology of SSCs and makes possible germ-line modification by sophisticated technologies. Moreover, the ability to recover, culture indefinitely, and transplant SSCs will make the germ-line of individual males available for periods extending beyond a normal lifetime. 相似文献
968.
Katayama T Nakashima H Takagi C Honda Y Suzuki S Iwasaki Y Yamamoto T Yoshioka M Yano K 《International heart journal》2005,46(5):771-781
The aim of the present study was to investigate the prognostic significance of time-delay to peak creatine kinase (CK) after successful direct percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Our 240 consecutive first AMI attack subjects admitted within 5 hours from onset were successfully reperfused by direct PCI therapy. Subjects were divided into two groups according to the upper quartile value of peak-CK time from onset, the early peak-CK group (peak-CK time < or = 16 hours from onset, n = 180) and the late peak-CK group (peak-CK time > 16 hours, n = 60). (I) The early ST-segment resolution rate was lower in the late peak-CK group compared with the early peak-CK group (P < 0.05), and there were significantly fewer patients with preinfarction angina pectoris in the late peak-CK group than in the early peak-CK group (P < 0.01). (II) LVEF in the chronic stage was significantly lower in the late peak-CK group than in the early peak-CK group (49 +/- 13% versus 57 +/- 13%, P < 0.001). (III) There were significantly more patients with major complications in the late peak-CK group than in the early peak-CK group (required CABG: 10% versus 3%, P < 0.05; cardiac death: 18% versus 3%, P = 0.0001). (IV) Multivariate analysis identified late peak-CK as an independent predictor of cardiac death (Odds ratio 7.91, 95% C.I. 1.40-44.11, P < 0.05). In patients with AMI, the time-delay to peak-CK after successful direct PCI may be closely related to left-ventricular systolic dysfunction and poor patient outcome, including mortality. 相似文献
969.
H Ashida J Utsunomiya Y Kotoura Y Ishikawa A Nishioka K Takagi M Fukuda 《Journal of clinical gastroenterology》1989,11(6):658-662
From December 1973 to December 1987, we performed a distal splenorenal shunt (DSRS) in 112 cases of portal hypertension, including 107 with postnecrotic liver cirrhosis and 5 with idiopathic portal hypertension (IPH). They comprised about 50% of our surgical cases with esophageal varices. In 1981, we modified our operative procedure towards a more extended splenopancreatic disconnection (SPD) in order to prevent the "stealing" of the shunt through the pancreatic vein. In one group of 69 patients who underwent DSRS alone, the operative mortality was 2.9%; postoperative encephalopathy was seen in 17.4%, late hepatic failure in 40.6%, and recurrence of varices in 4.3%. In the other group, 43 patients who underwent DSRS with SPD, there were no operative deaths, no encephalopathy (better than DSRS alone at p less than 0.05), and late hepatic failure was seen in only 9.3% (better than DSRS alone at p less than 0.025), while the recurrence rate of 7% was the only statistical increase. These data show that DSRS + SPD can improve chances of survival. 相似文献
970.
Pulmonary sarcoidosis with associated bloody pleurisy 总被引:1,自引:0,他引:1
Watarai M Yazawa M Yamanda K Yamamoto H Yamazaki Y 《Internal medicine (Tokyo, Japan)》2002,41(11):1021-1023
A 64-year-old man was admitted to our hospital complaining of non-productive cough and right chest pain. Chest radiographs showed bilateral hilar lymphadenopathy, diffuse granular nodules and right pleural effusion. Serum angiotensin-II-converting enzyme and lysozyme levels were elevated. Since thoracentesis indicated bloody pleurisy, video-assisted thoracoscopy was performed and revealed multiple white nodules on both the visceral and parietal pleura. Resected pleural biopsy specimens showed non-caseous granulomas. Furthermore, some nodules were observed to compress and involve small vessels and capillaries. The bloody pleurisy was assumed to have been derived from the rupture of small vessels that had been compressed and affected by the granuloma with sarcoidosis. 相似文献