全文获取类型
收费全文 | 35748篇 |
免费 | 2476篇 |
国内免费 | 2646篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 470篇 |
妇产科学 | 99篇 |
基础医学 | 2370篇 |
口腔科学 | 21篇 |
临床医学 | 4341篇 |
内科学 | 10636篇 |
皮肤病学 | 127篇 |
神经病学 | 205篇 |
特种医学 | 2644篇 |
外科学 | 7802篇 |
综合类 | 4386篇 |
预防医学 | 1488篇 |
眼科学 | 3篇 |
药学 | 2811篇 |
12篇 | |
中国医学 | 1182篇 |
肿瘤学 | 2261篇 |
出版年
2024年 | 64篇 |
2023年 | 532篇 |
2022年 | 1156篇 |
2021年 | 1355篇 |
2020年 | 1197篇 |
2019年 | 989篇 |
2018年 | 1014篇 |
2017年 | 905篇 |
2016年 | 1151篇 |
2015年 | 1299篇 |
2014年 | 2459篇 |
2013年 | 2107篇 |
2012年 | 2263篇 |
2011年 | 2338篇 |
2010年 | 2170篇 |
2009年 | 2196篇 |
2008年 | 2250篇 |
2007年 | 2197篇 |
2006年 | 2102篇 |
2005年 | 1701篇 |
2004年 | 1193篇 |
2003年 | 1061篇 |
2002年 | 967篇 |
2001年 | 852篇 |
2000年 | 728篇 |
1999年 | 585篇 |
1998年 | 518篇 |
1997年 | 470篇 |
1996年 | 395篇 |
1995年 | 376篇 |
1994年 | 368篇 |
1993年 | 262篇 |
1992年 | 235篇 |
1991年 | 178篇 |
1990年 | 149篇 |
1989年 | 142篇 |
1988年 | 132篇 |
1987年 | 89篇 |
1986年 | 79篇 |
1985年 | 89篇 |
1984年 | 62篇 |
1983年 | 37篇 |
1982年 | 59篇 |
1981年 | 63篇 |
1980年 | 44篇 |
1979年 | 37篇 |
1978年 | 51篇 |
1977年 | 37篇 |
1976年 | 34篇 |
1974年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
David M. Warshauer Richard C. Semelka Susan M. Ascher 《Journal of magnetic resonance imaging : JMRI》1994,4(4):553-557
Small nodular lesions in the liver and spleen have been reported as an infrequent manifestation of sarcoidosis. Five patients with this appearance on either dynamic contrast material—enhanced computed tomographic (CT) or ultrasound scans underwent magnetic resonance (MR) imaging with and without dynamic gadolinium enhancement. The lesions were relatively uniform in size, ranging from 0.5 to 1.5 cm. On CT scans, they were hypoattenuating relative to surrounding parenchyma. On MR images, the lesions were hypointense relative to background parenchyma with all sequences. No substantial enhancement was observed in the lesions, although lesion conspicuity decreased over time on serial postcontrast images. Lesion conspicuity was greatest on either T2-weighted fat-suppressed (T2FS) images or early-phase dynamic contrast-enhanced images. Abdominal adenopathy was seen in three of the five patients and was hyperintense relative to liver on T2FS images in two and intermediate in intensity in one patient. 相似文献
92.
S. Friman H. Persson T. Scherstn J. Svanvik I. Karlberg 《Transplant international》1992,5(Z1):S187-S189
Acute rejection, occurring with a reported frequency of 50–70%, is still a dominating problem after liver transplantation. Medication with ursodeoxycholic acid (UDCA) has beneficial effects in different cholestatic conditions and has also been shown to reduce HLA class I antigen expression on hepatocytes in patients with PBC. Since August 1989 we have consecutively treated all patients with primary graft function with UDCA (n = 41). Patients transplanted in the first half of 1989 served as a control group (n = 8). All patients in this study were given sequential quadruple drug immunosuppression. The treatment group were given oral UDCA 10 mg/kg per day. During the first postoperative month, 17% of the UDCA-treated patients had an episode of acute rejection compared with 75% of the control patients (P < 0.01). Liver biochemistry tests 1 month postoperatively were significantly better in patients treated with UDCA. The results suggest that adjuvant treatment with UDCA reduces acute liver graft rejection. 相似文献
93.
Richard C. Semelka Suvipapun Worawattanakul Nikolaos L. Kelekis Gesine John John T. Woosley Mark Graham William G. Cance 《Journal of magnetic resonance imaging : JMRI》1997,7(6):1040-1047
This study compares liver lesion detection, characterization, and effect on patient management between single-phase spiral CT and MRI using spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo, and serial post gadolinium SGE. All patients with suspected liver lesions who underwent spiral CT and MRI within a 1-month period between January 1993 and September 1996 were included in the study. Spiral CT and MRI were interpreted prospectively in a blinded fashion by separate individual experienced investigators, and lesion detection and characterization were determined. Confirmation was obtained by surgery (6 patients), biopsy (18 patients), imaging follow-up (36 patients), or combined reading of all imaging studies and clinical follow-up (29 patients). Effect on patient management was determined by combined chart review and interview of the patients' physicians and by retrospective clinical assessment performed by a surgical oncologist and medical oncologist separately. Eighty-nine patients were included in the study. Regarding true positive lesion detection, 295 and 519 lesions were detected on spiral CT and MR images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were detected on MR than on spiral CT in 44 of 89 patients (49.4%), and 11 of these 44 patients had lesions shown on MRI in whom no lesions were apparent on CT images. No patients had true positive lesions shown on spiral CT that were not shown on MRI. Regarding lesion characterization, 129 and 466 lesions were characterized on spiral CT and MRI images, respectively, which was significantly different on a patient-by-patient basis (P < .001). More lesions were characterized on MR than CT images in 67 patients (75.3%). Regarding effect on patient management, chart review with physician interview demonstrated that findings on MRI provided information that altered patient management as compared with findings on spiral CT in 57 patients. Retrospective clinical evaluation by the surgical and medical oncologist showed that MRI was considered to have a greater effect on patient management than spiral CT in 58 and 55 patients, respectively. Comparing current MRI technique to single-phase spiral CT, MRI detected more lesions in 49.4% and characterized more lesions in 75.3% of patients investigated for focal liver disease. MRI had a greater effect on patient management in each of the three methods than singlephase spiral CT in more than 61% of patients. 相似文献
94.
目的 :探讨各种肝病患者血清肝纤维化标志的改变 ,甘草酸二胺注射液对肝脏炎症、纤维化指标的作用。方法 :用放免法检测透明质酸 (HA)、层粘蛋白 (LN)、Ⅲ型前胶原多肽 (PCⅢ )。结果 :急性肝炎的三种肝纤指标均升高 (P <0 0 5 )。急黄肝高于急无黄肝 (P <0 0 5 )。慢性肝炎 1 1 2例 ,三项肝纤指标显著高于正常对照 (P <0 0 5 )。慢肝重度显著高于慢肝轻度 (P<0 0 0 1 )。肝硬化的三项肝纤指标又显著高于慢肝 (P <0 0 0 1 ) ,其它肝病的肝纤指标也升高。 2 5例慢肝用甘草酸二胺注射液治疗 2月 ,ALT、AST、GGT显著降低 (P <0 0 1 )。三项肝纤指标中HA降低较显著 (P =0 0 5 ) ,LN和PCⅢ虽有降低 ,但差异不明显 (P =0 4 5 9,P =0 1 92 )。结论 :各种肝病的三项肝纤维化指标均升高 ,以慢肝重度 ,肝硬化升高明显。甘草酸二胺注射液治疗有抗炎及改善肝纤维化的作用 相似文献
95.
泡型肝包虫病的超声诊断再探讨-附100例分析 总被引:1,自引:1,他引:0
目的:探讨泡型肝包虫病的B超特征,提出分型依据。方法:综合分析100例经手术或穿刺病理证实的B超声像图表现,并结合部分经CT、MRI检查病例对比研究。结果:100例泡型肝包虫,B超主要表现为①肝内不规则强回声团块80例,其中团块内呈弥漫性粗颗粒状强回声类似"落雪状"改变25例,团块内合并坏死液化20例,团块内钙化25例,钙化和液化同时出现10例。②肝内呈结节状改变20例。结论:泡型肝包虫病表现有其特征性,团块内粗颗粒状强回声,不规则液化坏死,斑片状钙化,周边无低回声暗晕以及彩超团块内无血流信号是与肝癌等肿块鉴别的重要依据。 相似文献
96.
Antonio Giorgio M.D. Luciano Tarantino Giampiero Francica Nicola Mariniello Antonio Nuzzo Luca del Viscovo Antonio Rotondo 《Cardiovascular and interventional radiology》1996,19(1):27-31
Purpose: To verify the efficacy of ultrasound (US)-guided injection of large amounts of ethanol into large or multiple liver lesions,
in a single session under general anesthesia (one-shot PEI) for percutaneous ablation of hepatic tumors.
Methods: Twenty-nine patients (27 with 51 hepatocellular carcinoma (HCC) nodules on cirrhosis, diameter range 1.0<+>–<+>9.0 cm; two
patients with a single metastasis from the gastroenteric tract, 5.0 and 9.0 cm, respectively, in diameter) were treated with
one-shot PEI.
Results: The total volume of alcohol delivered per patient ranged from 16 to 210 ml. Mean ethanol volume in all patients was 49 ml.
Dynamic computed tomography (CT) examination showed complete necrosis in 41 of 50 lesions. Two patients died of hypovolemic
shock due to massive upper gastrointestinal bleeding, 3 and 7 days, respectively, after the interventional procedure. All
the remaining patients are alive (follow-up 5<+>–<+>14 months) except one who died of liver failure 5 months after. New HCC
nodules occurred in six patients within 6 months and one intralesional relapse was recorded.
Conclusion: In this preliminary experience, one-shot PEI is as effective in inducing liver tumor necrosis as traditional PEI; its advantages
are shorter treatment time and the capability of treating larger and multiple liver lesions. 相似文献
97.
The effects of regular daily coffee consumption on liver enzymes were studied in a large number of subjects from the general population. In coffee drinkers, liver enzymes (gamma-glutamyl transferase, alkaine-amino transferase, and alkaline phosphatase) and serum bilirubin were lower than in non-coffee-drinking subjects or in those consuming less than 3 cups daily. The hypothesis proposed is that liver enzymes are a target for caffeine contained in coffee. 相似文献
98.
经皮穿刺氩氦刀冷冻治疗肝癌56例临床分析 总被引:11,自引:0,他引:11
目的 探讨氩氦刀冷冻治疗肝脏恶性肿瘤的临床意义。方法 2 0 0 1年 7月~ 2 0 0 2年6月 5 6例肝脏恶性肿瘤在B型超声引导下行经皮穿刺氩氦刀冷冻治疗。术后患者定期复查血清肿瘤标记物、B型超声检查及CT或MRI。结果 患者肝功能ChildA级 5 0例 ,ChildB级 5例 ,ChildC级 1例。原发性肝癌 4 6例 ,转移性肝癌 10例。小肝癌 (直径≤ 5cm)甲胎蛋白阳性者治疗后转阴占80 % ,甲胎蛋白阴性者治疗后CT或MRI复查病灶完全坏死达 6 1.5 %。转移性肝癌治疗后瘤标降至正常或CT、MRI提示病灶完全坏死者占 6 0 %。结论 氩氦刀冷冻治疗肝脏恶性肿瘤是一种微创、安全、疗效可靠的新方法。对于不适宜行手术治疗的肝脏恶性肿瘤患者是一种有效的微创外科治疗方法。 相似文献
99.
目的研究大鼠肝移植后自发免疫耐受的形成与移植肝内CD4~ CD25~ 调节性T细胞(Tr细胞)的关系。方法按供、受者不同将实验分为3组。急性排斥组:DA大鼠为供者,LEW大鼠为受者;自发耐受组:LEW大鼠为供者,DA大鼠为受者;同基因组:供、受者均为DA大鼠。各组均建立大鼠原位肝移植模型。分别在肝移植术后4、7、14、30和90 d时采用密度梯度离心法分离移植肝内淋巴细胞,免疫磁珠分离(MACS)法分选出CD4~ CD25~ Tr细胞;用流式细胞术(FCM)检测细胞纯度,同时分析CD4~ CD25~ Tr细胞比例的变化;体外细胞增殖试验研究CD4~ CD25~ Tr细胞对CD4~ CD25~-T细胞的免疫抑制作用。结果肝移植早期,急性排斥组和自发耐受组移植肝内CD4~ CD25~ Tr细胞比例均明显增加,其中急性排斥组增加更为明显;移植后4 d左右,两组CD4~ CD25~ Tr细胞比例开始下降,急性排斥组的下降幅度较大;移植后30 d,自发耐受组受者的移植肝内CD4~ CD25~ Tr细胞比例达到第2次高峰,约在移植后90 d时下降至正常生理水平。移植后7 d左右,急性排斥组受者均因发生排斥反应而死亡,而自发耐受组受者均存活。此外,CD4~ CD25~ Tr细胞能有效抑制CD4~ CD25~-T细胞的增殖。结论CD4~ CD25~ Tr细胞是一种具有特异免疫调节功能的T细胞亚群,其主动的免疫抑制功能可能是诱导大鼠肝移植自发免疫耐受的机制之一。 相似文献
100.
目的 探讨原位肝移植术后胆道狭窄的病因及治疗方法.方法 回顾性分析2006年5月至2008年9月间90例肝移植受者的临床资料,对术后发生胆道狭窄的病因和治疗方法进行了探讨.结果 90例肝移植受者中,术后有8例发生胆道狭窄并发症(8.89%),其中吻合口狭窄5例,非吻合口狭窄3例.吻合口狭窄中,有3例因炎症水肿引起狭窄,经内镜逆行胆管造影(ERC)球囊扩张或置入胆道支架治疗后痊愈;另2例因吻合口胆漏疤痕收缩导致狭窄,经ERC置入胆道塑料支架,1例狭窄消失,1例好转.3例非吻合口狭窄者,均为弥漫性肝内胆管狭窄,经ERC或经皮肝穿刺胆道造影(PTC),采用球囊扩张和胆道支架置入治疗效果不佳,2例行二次肝脏移植后获救,1例治疗无效死亡.结论 吻合口狭窄和非吻合口狭窄的病因对治疗的反应存在差异,因此,要重视肝移植术后胆道狭窄的病因诊断和分析.只要及时采取适当的治疗措施,均可有效地治疗肝移植术后胆道狭窄. 相似文献