首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12579篇
  免费   712篇
  国内免费   180篇
耳鼻咽喉   213篇
儿科学   107篇
妇产科学   164篇
基础医学   1796篇
口腔科学   362篇
临床医学   911篇
内科学   2837篇
皮肤病学   378篇
神经病学   833篇
特种医学   753篇
外科学   1836篇
综合类   38篇
一般理论   3篇
预防医学   332篇
眼科学   340篇
药学   1155篇
中国医学   112篇
肿瘤学   1301篇
  2023年   76篇
  2022年   250篇
  2021年   348篇
  2020年   175篇
  2019年   313篇
  2018年   352篇
  2017年   307篇
  2016年   455篇
  2015年   578篇
  2014年   619篇
  2013年   715篇
  2012年   1106篇
  2011年   1035篇
  2010年   630篇
  2009年   497篇
  2008年   693篇
  2007年   650篇
  2006年   590篇
  2005年   574篇
  2004年   430篇
  2003年   435篇
  2002年   424篇
  2001年   239篇
  2000年   242篇
  1999年   183篇
  1998年   82篇
  1997年   52篇
  1996年   36篇
  1995年   36篇
  1994年   38篇
  1993年   29篇
  1992年   96篇
  1991年   101篇
  1990年   97篇
  1989年   118篇
  1988年   94篇
  1987年   86篇
  1986年   76篇
  1985年   82篇
  1984年   69篇
  1983年   46篇
  1981年   23篇
  1980年   31篇
  1979年   44篇
  1978年   25篇
  1972年   24篇
  1970年   24篇
  1968年   36篇
  1967年   26篇
  1966年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We report a case of a 57-year-old patient with a history of a Starr-Edwards mitral valve prosthesis and DeBakey-Surgitool aortic valve prosthesis implanted 30 years ago who presented with symptoms consistent with class IV heart failure. The patient had been on no anticoagulation for approximately 30 years secondary to recurrent epistaxis occurring two years after starting warfarin therapy postoperatively. Throughout the patient's lifetime he experienced no thromboembolic complications from the lack of anticoagulation, despite developing concomitant atrial fibrillation approximately ten years prior to admission. In place of warfarin the patient had substituted large doses of aspirin. A workup revealed normal function of the mechanical valves for this extensive period.  相似文献   
992.
Background In rectal cancer patients treated with preoperative chemoradiotherapy (CRT) and curative resection, we evaluated the effect of clinical parameters on lateral pelvic recurrence and made an attempt to identify a risk factor for lateral pelvic recurrence. Methods The study involved 366 patients who underwent preoperative CRT and curative resection between October 2001 and December 2005. Clinical parameters such as gender, age, tumor size, histologic type, cT and cN classification, ypT and ypN classification, circumferential resection margin, tumor regression grade, chemotherapeutic regimen, and lateral lymph node size were analyzed to identify risk factors associated with lateral pelvic recurrence. Results Of the 366 patients, 29 patients (7.9%) had locoregional recurrence: 6 (20.7%) with central pelvic recurrence and 24 (82.7%) had lateral pelvic recurrence, of which 1 had simultaneous central and lateral pelvic recurrence. Multivariate analysis showed that ypN classification and lateral lymph node size were significantly associated with lateral pelvic recurrence (P < .001). Of 250 ypN0 patients, lateral pelvic recurrence developed in 1.4%, 2.9%, and 50% of patients with lateral lymph node sizes of <5, 5-9.9, and ≥10 mm, respectively (P < .001). Of 116 ypN+ patients, lateral pelvic recurrence developed in 4.3%, 35.7%, and 87.5% of patients with lateral lymph node sizes of <5, 5–9.9, and ≥10 mm, respectively (P < .001). Conclusions In our study, lateral pelvic recurrence was a major cause of locoregional recurrence, and ypN+ and lateral lymph node size were risk factors for lateral pelvic recurrence.  相似文献   
993.
Dysfunction in configural face processing in patients with schizophrenia   总被引:1,自引:0,他引:1  
BACKGROUND: Face recognition has important implications for patients with schizophrenia, who exhibit poor interpersonal and social skills. Previous reports have suggested that patients with schizophrenia have deficits in their ability to recognize faces, and because face recognition relies heavily on information about the configuration of faces, we hypothesized that patients with schizophrenia would have specific problems in processing configural information. METHODS: We measured the performance of 20 patients with schizophrenia and 20 normal subjects in a face-discrimination task, using upright and inverted pairs of face photographs that differed in featural or configural information. RESULTS: The patients with schizophrenia showed disproportionately poorer performance in discriminating configural compared with featural face sets. CONCLUSION: The result suggests that the face-recognition deficit in schizophrenic patients is due to specific impairments in configural processing of faces.  相似文献   
994.
995.
996.
PURPOSE: To describe our experience with a bolus injection of 5-fluorouracil and leucovorin (FL) vs. capecitabine in terms of radiologic and pathologic findings in preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer. METHODS: The study enrolled 278 patients scheduled for preoperative CRT using two protocols with different chemotherapeutic regimens. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with FL (n = 145) or capecitabine (n = 133). Surgery was performed 6 weeks after CRT completion. Tumor responses to CRT were measured using both radiologic and pathologic examination. Magnetic resonance volumetry was performed at the initial workup and just before surgery after completion of preoperative CRT. Post-CRT pathology tests were used to determine tumor stage and regression. RESULTS: Radiologic examination showed that tumor volume decreased by 68.2% +/- 20.5% in the FL group and 68.3% +/- 22.3% in the capecitabine group (p = 0.970). Postoperative pathologic T stage determination showed that downstaging occurred in 44.3% of FL and 49.9% of capecitabine patients (p = 0.571). The tumor regression grades after CRT were Grade 1 (minimal response) in 22.6% and 21.0%, Grade 2 (moderate response) in 53.2% and 50.0%, Grade 3 (near-complete response) in 12.9% and 12.9%, and Grade 4 (complete response) in 11.3% and 16.1% of the FL and capecitabine groups, respectively (p = 0.758). CONCLUSION: In the present study, the radiologic and pathologic findings did not reveal significant differences in short-term tumor responses between preoperative FL and capecitabine CRT for locally advanced rectal cancer. Long-term results and a prospective randomized trial are needed.  相似文献   
997.
Lee MK  Kim HR  Kang JO  Kim MN  Kim EC  Kim JS  Kim JJ  Park YJ  Song W  Shin JH  Lee KM  Lee NY  Lee M  Lee WG  Lee CK  Lee HJ  Chang CL  Choi TY 《Mycoses》2007,50(2):148-149
The work reported here is the first nationwide, multicenter surveillance study conducted in Korea to obtain data on fluconazole susceptibility of Candida albicans (C. albicans) isolates. A total of 1137 isolates of C. albicans obtained from 17 university hospitals in South Korea during the 6-month period, July through December 2004, were tested. No resistant strains were observed in any of the isolates. Only five of the 1137 isolates (0.44%) of C. albicans were found to be susceptible dose dependent, with all remaining strains (99.56%) susceptible to fluconazole. Trailing growth at 48 h was found in only four isolates (0.35%).  相似文献   
998.
999.
Up-regulated claudin 7 expression in intestinal-type gastric carcinoma   总被引:1,自引:0,他引:1  
The disruption of tight junction protein expression in cancer might account for invasiveness, loss of cohesion, and lack of differentiation. Our cDNA array data indicated that claudin 7 was up-regulated in gastric carcinoma. We investigated the expression patterns and clinical implications of claudin 7 in gastric cancer. By immunohistochemical staining and Western blot, claudin 7 was significantly more often expressed in intestinal metaplasia, adenoma and cancer than in normal gastric epithelium. Twenty-seven (47.4%) of 57 normal gastric epithelium samples did not express claudin 7, but 50 (86.2%) of 58 intestinal metaplasia, 11 (91.7%) of 12 adenoma tissues, and 129 (82.7%) of 156 cancer samples did. Claudin 7 was more often unexpressed in diffuse type gastric cancer than in intestinal type. Only 13 (11.2%) of 116 intestinal type samples did not express claudin 7, but 14 (41.2%) of 34 diffuse type samples showed no expression. Compared to normal gastric epithelium, intestinal type gastric cancer significantly more often expressed claudin 7, but diffuse type did not. The expression pattern of claudin 7 did not change as cancer progressed. In this study we show that claudin 7 expression changed with the gastric carcinogenic process and that this is implicated in cancer characteristics.  相似文献   
1000.
Kang DG  Choi DH  Lee JK  Lee YJ  Moon MK  Yang SN  Kwon TO  Kwon JW  Kim JS  Lee HS 《Planta medica》2007,73(14):1436-1440
Cornuside is a bisiridoid glucoside compound isolated from the fruit of CORNUS OFFICINALIS Sieb. et Zucc. (Cornaceae). In the present study, we investigated the effect of cornuside on vascular tone in rat aortic tissue. Cornuside induced a concentration-dependent relaxation of the phenylephrine-precontracted rat aorta, which was abolished by removal of the endothelial layer. Pretreatment of the aortic tissues with either N(G)-nitro- L-arginine methyl ester (L-NAME) or 1 H- -oxadiazole-[4,3-alpha]-quinoxalin-1-one (ODQ) completely inhibited the relaxation induced by cornuside. However, the relaxant effect of cornuside was not blocked by pretreatment with verapamil, diltiazem, tetraethylammonium (TEA), glibenclamide, indomethacin, atropine, or propranolol. In addition, incubation of human umbilical vein endothelial cells (HUVECs) with cornuside increased the production of cGMP in a dose-dependent manner, but this effect was blocked by pretreatment with L-NAME and ODQ, respectively. Taken together, the present study suggests that cornuside dilates vascular smooth muscle via endothelium-dependent nitric oxide (NO)/cGMP signaling.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号