全文获取类型
收费全文 | 45963篇 |
免费 | 5143篇 |
国内免费 | 3325篇 |
专业分类
耳鼻咽喉 | 504篇 |
儿科学 | 454篇 |
妇产科学 | 416篇 |
基础医学 | 4773篇 |
口腔科学 | 719篇 |
临床医学 | 5816篇 |
内科学 | 6237篇 |
皮肤病学 | 534篇 |
神经病学 | 2138篇 |
特种医学 | 1906篇 |
外国民族医学 | 12篇 |
外科学 | 5447篇 |
综合类 | 8996篇 |
现状与发展 | 17篇 |
一般理论 | 3篇 |
预防医学 | 3416篇 |
眼科学 | 1280篇 |
药学 | 5232篇 |
40篇 | |
中国医学 | 3047篇 |
肿瘤学 | 3444篇 |
出版年
2024年 | 191篇 |
2023年 | 891篇 |
2022年 | 2040篇 |
2021年 | 2776篇 |
2020年 | 2177篇 |
2019年 | 1668篇 |
2018年 | 1695篇 |
2017年 | 1672篇 |
2016年 | 1488篇 |
2015年 | 2325篇 |
2014年 | 2702篇 |
2013年 | 2814篇 |
2012年 | 3774篇 |
2011年 | 4082篇 |
2010年 | 2903篇 |
2009年 | 2283篇 |
2008年 | 2660篇 |
2007年 | 2550篇 |
2006年 | 2321篇 |
2005年 | 2161篇 |
2004年 | 1463篇 |
2003年 | 1229篇 |
2002年 | 1070篇 |
2001年 | 859篇 |
2000年 | 777篇 |
1999年 | 751篇 |
1998年 | 345篇 |
1997年 | 362篇 |
1996年 | 313篇 |
1995年 | 293篇 |
1994年 | 216篇 |
1993年 | 137篇 |
1992年 | 205篇 |
1991年 | 188篇 |
1990年 | 170篇 |
1989年 | 161篇 |
1988年 | 124篇 |
1987年 | 100篇 |
1986年 | 77篇 |
1985年 | 54篇 |
1984年 | 56篇 |
1983年 | 30篇 |
1982年 | 28篇 |
1981年 | 39篇 |
1980年 | 26篇 |
1979年 | 36篇 |
1978年 | 33篇 |
1977年 | 20篇 |
1975年 | 15篇 |
1974年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
51.
52.
目的:研究治疗前列腺增生的α1-受体拮抗剂SL-89.0519-08的合成路线。方法:以5-氯-2-甲氧基苯胺为原料,经环合,烃化,脱保护基和亲核取代等步骤,合成了目标化合物,同时对原料合成工艺进行了摸索。结果:合成的目标化合物经IR,^1HMNR,EI-MS和HRMS得以确证。结论:该合成工艺和路线适宜工业化生产。 相似文献
53.
目的:探讨腹腔镜在腹股沟疝修补手术中的优缺点,方法:31例腹股沟疝行腹腔镜疝修补术,其中斜疝25例,直疝6例,复发疝4例,均行腹腔内术式(TAPP)。结果:手术全部完成,平均手术时间61min(40-95min),无中转手术,4例同时行胆囊切除术,平均住院7.5d,术后近期随访无复发,结论:腹腔镜疝修补术是一种安全的手术,术后恢复时间短,复发率低。 相似文献
54.
赤芍总苷对沙土鼠全脑缺血再灌注损伤的保护作用 总被引:3,自引:0,他引:3
OBJECTIVE: To study the protective effects of the total paeony glycoside (TPG) against global cerebral ischemia-reperfusion injury in gerbils. METHODS: Gerbils models of global cerebral ischemia-reperfusion injury were prepared by bilateral common carotid artery ligation for 12 min followed by 24-hour reperfusion. The effects of TGP on brain edema index, superoxide dismatase (SOD) activity and malonaldehyde (MDA) concentration of the cerebral tissue homogenate and pathology of the brain were examined 24 h after model establishment. RESULTS: Compared with the model group, TPG at the doses of 200 and 400 mg/kg could significantly relieve brain edema, enhance SOD activity and lower MDA concentration in the gerbils. Pathological examination showed that the gerbils with TPG treatment had milder injury of the cells in the hippocampal CA1 region. CONCLUSIONS: TPG has obvious protective effects against global cerebral ischemia-reperfusion injury. 相似文献
55.
Effects of vasodilator drugs on venous tone in conscious rats 总被引:1,自引:0,他引:1
The dose-response effects of vasodilator drugs, nitroglycerin, sodium nitroprusside and hydralazine, on mean arterial pressure (MAP) and mean circulatory filling pressure (MCFP), an index of body venous tone, were investigated in conscious, unrestrained, intact rats as well as in rats treated with the ganglionic blocker, hexamethonium. The effects of these drugs were compared with those of the vehicle, normal saline, in control rats. In intact rats, i.v. infusion of nitroglycerin did not alter MAP while i.v. infusions of nitroprusside or hydralazine caused dose-dependent decreases in MAP. After ganglionic blockade, all three drugs decreased MAP. In intact rats, nitroglycerin and sodium nitroprusside did not affect MCFP but hydralazine increased MCFP. After treatment with hexamethonium, all three drugs decreased MCFP. The decreases in MCFP caused by nitroglycerin and nitroprusside, but not that by hydralazine, were significantly greater than the corresponding changes in control rats. Thus, in intact rats, the direct venodilator actions of nitroprusside and nitroglycerin were masked by endogenous sympathetic tone. When sympathetic nerve activity was attenuated, both nitroprusside and nitroglycerin have venodilator effects. Hydralazine, on the other hand, had insignificant venodilator effect both in the presence and absence of sympathetic reflexes. 相似文献
56.
目的探讨NO合成底物左旋-精氨酸(L-Arg)对兔局灶脑缺血后血管再生和脑细胞凋亡的影响。方法兔局灶脑缺血后应用L-Arg,流式细胞仪定量分析细胞凋亡率的变化,CD34免疫组织化学测脑组织微血管密度(MVD),脑组织含水率评价脑水肿。结果与对照组比较,L-Arg组脑细胞凋亡率明显减少(8.72±2.62 vs 16.62±2.82,P<0.01),同时脑组织MVD却明显增加(1.21±0.43 vs 0.69±0.22,P<0.01)。结论外源性L-Arg可减少缺血后脑细胞凋亡并促进缺血后血管再生,对局灶脑缺血具有重要的神经保护作用。 相似文献
57.
BACKGROUND: As a non-invasive technique which can provide comprehensive biological information, 1H-magnetic resonance spectroscopy (1H-MRS) may provide valuable reference data for irreversible recovery or reversible changes in ischemic tissue after stroke.
OBJECTIVE: To monitor and evaluate the effect of the urokinase thrombolytic therapy after experimental acute cerebral ischemia by 1H-MRS technology and investigate its adaptability.
DESIGN: Randomly controlled animal study.
SETTINGS: Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science.
MATERIALS: Eleven healthy adult Sprague-Dawley (SD) rats, weighing 260–300 g and of both genders, were supplied by Experimental Animal Center of Tongji Medical Collage, Huazhong University of Science and Technology [SCXK (e) 2004-007]. 4.7T superconducting nuclear magnetic resonance meter was provided by Brucker Company.
METHODS: The experiment was carried out in Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science from August 2003 to December 2005. ① The rats were randomly divided into 30-minute self-thrombo-embolism group (n =6) and 60-minute self-thrombo-embolism group (n =5). Six rats in 30-minute self-thrombo-embolism group were occluded with clot embolus for 30 minutes and 5 rats in 60-minute self-thrombo-embolism group were occluded for 60 minutes. 10 000 U/kg urokinase was dissolved in 2 mL saline and the operation lasted for 5 minutes. ② 1H-MRS was performed before thrombolysis and at 3 hours and 24 hours after successful embolization. The metabolic changes of N-acetyl-L-aspartic acid (NAA)/phosphocreatine (PCr) + creatine (Cr), choline phosphate (Cho)/PCr+Cr and lactic acid (Lac)/PCr+Cr in the region of interests were analyzed. ③ The T2W image was conducted 24 hours after the thrombolytic therapy with TR=500 ms and TE=25 ms. ④ The subjects were sacrificed immediately after 1H-MRS and the brain tissues were cut into pieces and stained with HE method; in addition, pathological changes were observed under optic microscope.
MAIN OUTCOME MEASURES: ① Metabolic changes of NAA/PCr+Cr, Cho/PCr+Cr and Lac/PCr+Cr in the region of interests; ② T2W image at 24 hours after the thrombolysis; ③ pathological observation of brain tissue.
RESULTS: Eleven rats were all involved in the final analysis. ① Metabolic changes in the region of interests : In 30-minute self-thrombo-embolism group, the Lac peak emerged immediately after the embolism, but the ischemic zone decreased 3 hours after the thrombolytic therapy (0.252±0.01, 0.603±0.01, P < 0.01). Lac/(PCr+Cr) ratio was 0.290±0.01 at 24 hours after thrombolysis, which was higher than that at 3 hours after thrombolysis (P < 0.01). The NAA/ (PCr+Cr) ratio decreased significantly at 3 hours after the thrombolysis as compared with that before thrombolysis (0.922±0.16, 1.196±0.01, P < 0.05). In 60-minute self-thrombo-embolism group, the Lac/(PCr+Cr) ratio was higher at 3 hours after thrombolysis than that before thrombolysis (0.846±0.12, 0.601±0.11, P < 0.05) and the NAA/(PCr+Cr) decreased at 3 hours after the embolism. Fluctuation of NAA/ (PCr+Cr) ranged from 0.68 to 0.75 before thrombolysis and from 0.71 to 0.75 at 3 hours after thrombolysis. ② T2W image: T2W image showed that 2 subjects in 30-minute self-thrombo-embolism group whose Lac/NAA was higher than 0.7 suffered from intracranial hemorrhage. This meant that the subjects with Lac/NAA > 0.7 were more likely to suffer from intracranial hemorrhage. ③ Histological and morphological examinations: Optic microscope demonstrated that interspace surrounding nerve cells was widened at ischemic center; neurons were swelling; nucleus was stained lightly; pyknosis and mesenchymal edema were mainly observed in lateral cortex of brow and vertex and in lateral part of corpus striatum.
CONCLUSION: ①Compound parameters in ischemic area before thrombolysis should be regarded as an important predicting marker for thrombolytic therapy, effect evaluation and termination. ② 1H-MRS combining with other imaging technique is a detecting way for screening cases who are suitable for thrombolytic therapy. 相似文献
58.
桂林市传染病网络直报工作第一年效果分析 总被引:4,自引:2,他引:2
目的观察传染病网络直报系统启动一年来的传染病监测质量,探讨网络直报评价方法.方法描述研究网络直报工作效果.结果实行网络直报后,传染病从临床医生发现到疾病预防控制机构接到报告的平均时间由5.48 d缩短至1.67 d,报卡数量增加20.84%,21.03%的报告卡得到校正,网络直报覆盖率县辖区医院为96.55%,市城区为69.23%,79.21%的直报单位有专用电脑.结论网络直报的启用及其系统的建立,提高了桂林市传染病疫情报告的质量和水平,同时应尽快建立与之相应的疫情报告管理方法和标准. 相似文献
59.
目的总结胰岛素瘤的诊断方法和外科治疗效果。方法回顾性分析近26年来收治的胰岛素瘤137例患者的临床资料。结果男77例,女60例。137例均具有典型的Whipple三联症。B超,CT,MRI检查的阳性率分别为35.1%,67.9%,58.1%。126例手术治疗患者中,102例(80.9%)行胰岛素瘤摘除术,4例(3.2%)行胰十二指肠切除术,16例(12.7%)行胰体尾切除术,另外4例(3.2%)行开腹探查术。切除的122例肿瘤中,良性占96.7%,恶性3.3%;单发肿瘤98.4%,多发1.6%。86.9%肿瘤直径≤2.0cm。13.1%肿瘤位于胰头;位于胰体和胰尾者分别为46.7%和40.2%。结论Whipple三联症,结合IRI,IGR,C-肽,以及胰岛素原的检测水平,可作为胰岛素瘤的定性诊断依据。胰岛素瘤的定位诊断仍很困难,联合应用多种影像学检查方法有助于提高检出率。治疗首选肿瘤摘除术,如果术中探查未能找到肿瘤,不宜盲目行胰体尾切除术,应排除其他原因所致低血糖症,同时进一步完善影像学检查方法,明确定位后,再考虑二次手术治疗。 相似文献
60.
切开复位内固定治疗骨盆桶柄样Tilt骨折 总被引:1,自引:1,他引:0
目的探讨骨盆桶柄样Tilt骨折手术治疗方法。方法切开复位内固定治疗52例骨盆桶柄样Tilt骨折。前骨盆经Plan—nenstiel入路固定9例,Pfannenstiel入路结合部分髂腹般沟入路固定43例。37例行骨盆重建钢板固定,骨盆重建钢板固定结合耻骨上支髓内螺钉固定9例,6例2块骨盆重建钢板固定。后环37例经患侧髂嵴入路以骨盆重建钢板固定。8例骶骨骨折行骶髂关节螺钉固定。7例未行后骨盆固定。结果平均随访18个月。全部骨性愈合,无下肢不等长,骨盆畸形基本纠正。按Majeed疗效评定标准优良率为93.8%。结论通过前后联合入路,切开复位治疗骨盆桶柄样Tilt骨折疗效满意,并可防止远近期并发症的发生。 相似文献