全文获取类型
收费全文 | 242064篇 |
免费 | 20445篇 |
国内免费 | 14407篇 |
专业分类
耳鼻咽喉 | 2177篇 |
儿科学 | 3036篇 |
妇产科学 | 4881篇 |
基础医学 | 28322篇 |
口腔科学 | 4207篇 |
临床医学 | 30868篇 |
内科学 | 39822篇 |
皮肤病学 | 2817篇 |
神经病学 | 13554篇 |
特种医学 | 8535篇 |
外国民族医学 | 96篇 |
外科学 | 26649篇 |
综合类 | 34088篇 |
现状与发展 | 48篇 |
一般理论 | 45篇 |
预防医学 | 15088篇 |
眼科学 | 6680篇 |
药学 | 24204篇 |
164篇 | |
中国医学 | 10915篇 |
肿瘤学 | 20720篇 |
出版年
2024年 | 709篇 |
2023年 | 3490篇 |
2022年 | 8680篇 |
2021年 | 11424篇 |
2020年 | 8381篇 |
2019年 | 7591篇 |
2018年 | 7994篇 |
2017年 | 6970篇 |
2016年 | 6662篇 |
2015年 | 10088篇 |
2014年 | 12693篇 |
2013年 | 11880篇 |
2012年 | 17533篇 |
2011年 | 19212篇 |
2010年 | 11715篇 |
2009年 | 9378篇 |
2008年 | 12760篇 |
2007年 | 12805篇 |
2006年 | 12369篇 |
2005年 | 12447篇 |
2004年 | 8610篇 |
2003年 | 7644篇 |
2002年 | 6613篇 |
2001年 | 5990篇 |
2000年 | 6112篇 |
1999年 | 6410篇 |
1998年 | 3656篇 |
1997年 | 3669篇 |
1996年 | 2788篇 |
1995年 | 2584篇 |
1994年 | 2230篇 |
1993年 | 1496篇 |
1992年 | 2290篇 |
1991年 | 1995篇 |
1990年 | 1664篇 |
1989年 | 1454篇 |
1988年 | 1264篇 |
1987年 | 1176篇 |
1986年 | 941篇 |
1985年 | 748篇 |
1984年 | 491篇 |
1983年 | 381篇 |
1982年 | 225篇 |
1981年 | 201篇 |
1980年 | 191篇 |
1979年 | 243篇 |
1978年 | 141篇 |
1977年 | 112篇 |
1976年 | 97篇 |
1974年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
介绍了用混凝沉淀法预处理垃圾渗沥液试验。试验确定用浓度为0.1%的聚合硫酸铁作为混凝剂,并对混凝剂的投加量、pH、搅拌时间、搅拌速度、沉降时间等进行了试验研究。结果表明,混凝剂的投加量为0.5kg/m^3,pH为10,搅拌速度为110r/min,搅拌时间为60s时,处理效果最佳,CODc,去除率为25%,悬浮物去除率89%。 相似文献
892.
目的为了及时准确地掌握各类传染病的漏报情况,为制订传染病防治策略提供理论依据。方法每年对区、市、系统、乡级医疗机构疫情报告情况进行调查,计算漏报率。结果共调查传染病患者4069例,漏报130例.总平均漏报率为3.19%。年漏报率最低为0.53%;最高为10.39%。漏报病种最高为细菌性痢疾和病毒性肝炎.分别占总漏报数的53.85%和26.15%。结论领导重视、提高业务人员的能力和基层防保队伍的建设,是传染病疫情报告和管理工作顺利开展的保证。 相似文献
893.
Economic Burden of Patients with Anemia in Selected Diseases 总被引:1,自引:0,他引:1
William B. Ershler MD Kristina Chen PharmD MS Eileen B. Reyes Robert Dubois MD PhD 《Value in health》2005,8(6):629-638
894.
Colon transit study is currently performed by delivering technetium-99m or indium-111 labelled activated charcoal to the colon in a methacrylate-coated capsule (coated capsule). However, the coating procedure is complicated and methacrylate has not been approved by the Food and Drug Administration. Therefore, a simpler method is needed for the clinical routine use of colon transit study. In this study, we used a commercial empty enteric capsule and a coated capsule for the measurement of colon transit time. We compared the in vitro stability and in vivo scintigraphy of 99mTc-labelled activated charcoal in the coated capsule and the enteric capsule to evaluate the possibility of clinical usage of the enteric capsule for colon transit time study. Activated charcoal powder was mixed with 49mTc-diethylene triamine pentaacetic acid (DTPA) and vaporized to dryness. The dry 99mTc-DTPA activated charcoal was loaded into the coated capsule and the enteric capsule. In vitro stability study was performed by immersing these capsules in a colourless buffer of variable pH which mimicked the conditions in the stomach and the small bowel. Capsule disruption was determined. Colon transit scintigraphy with 99mTc-DTPA charcoal was performed in five normal volunteers using these two capsules. The in vitro stability of these two types of capsule was similar and the colon transit scintigraphy findings were almost identical. Most capsules dissolved in the ascending colon and very few in the terminal ileum. It is concluded that enteric capsule is a suitable alternative to coated capsule for measurement of colon transit. 相似文献
895.
896.
进入21世纪,我校的在校学生已达1万多人,繁重的教学任务迫切需要我们利用现代教育技术来提高教学水平. 相似文献
897.
1网络与现代生活:对焦虑、不安的宣泄 焦虑和不安正普遍地袭扰着现代人.不论是在校的学生还是社会其它领域的人们都不同程度地感受到来自生存竞争、环境恶化、疾病滋生和由失望、落败、不满等心理情绪无从排解而带来的对外界的不安全感和对人生意义的空缺感. 相似文献
898.
Rabbits were infused with H7, a general protein kinase inhibitor, into the region of the cerebellar interpositus nucleus during classical eyeblink conditioning. Acquisition of the conditioned eyeblink response was delayed by the H7 infusion, but the protein kinase inhibitor had no effect on performance of the learned response when infused after asymptotic learning had been reached. These data indicate that protein kinases in the cerebellum are involved in plasticity processes that underlie the learning of this simple conditioned behavior. 相似文献
899.
Delayed Administration of the K+ Channel Activator Cromakalim Attenuates Cerebral Vasospasm after Experimental Subarachnoid Hemorrhage 总被引:12,自引:0,他引:12
Summary ? Background. Delayed cerebral vasospasm remains an unpredictable and inadequately treated complication of aneurysmal subarachnoid hemorrhage
(SAH). Recent evidence indicates that the potassium channel activator cromakalim is capable of limiting cerebral vasospasm
in rabbits when administered immediately after experimental SAH (i.e. before spastic constriction has been initiated). However,
the ultimate clinical value of cromakalim for treating vasospasm will depend in part on its effectiveness when administered
after SAH-induced constriction has already been initiated. The present study examined the effects of cromakalim on vasospasm
when treatment was initiated after SAH-induced constriction was underway.
Methods. New Zealand white rabbits were subjected to experimental SAH by injecting autologous blood into the cisterna magna. Cromakalim
(0.03, 0.1 or 0.3 mg/kg) or vehicle was injected intravenously at 8 hour intervals beginning 24 hours post-SAH. Animals were
killed by perfusion fixation 48 hours after SAH. Basilar arteries were removed and sectioned, and cross-sectional area was
measured.
Findings. The average cross sectional areas of basilar arteries were reduced by 64% and 68% in the SAH-only and SAH+vehicle groups,
respectively. Treatment with cromakalim dose-dependently attenuated SAH-induced constriction. The groups treated with 0.03,
0.1, and 0.3 mg/kg cromakalim exhibited average decreases in cross-sectional area of 57%, 42%, and 19%, respectively.
Interpretation. These findings indicate that cromakalim dose-dependently attenuates cerebral vasospasm when administered 24 hours after experimental
SAH in the rabbit. The results suggest KATP channel activators, such as cromakalim, could be of benefit for reversing cerebral vasospasm after aneurysmal SAH. 相似文献
900.
Chen WM Engh CA Hopper RH McAuley JP Engh CA 《The Journal of bone and joint surgery. American volume》2000,82(2):197-206
BACKGROUND: Massive deficiency of acetabular bone stock is a challenging problem in the increasing number of patients who need a revision of a failed hip arthroplasty. The bilobed cup has been presented as one alternative reconstruction technique for hips with extensive acetabular bone loss. The purpose of this study was to assess the results with use of a bilobed acetabular component inserted without cement for revision reconstruction in hips with acetabular bone deficiency in order to clarify the indications for its use and to identify the factors that influence the clinical and radiographic outcome. METHODS: Forty-one hips in thirty-eight patients had an acetabular revision with a bilobed acetabular component inserted without cement between December 1991 and December 1995. These hips were a subset of the 414 hips treated with an acetabular revision during the same period of time. One patient was lost to follow-up, and one died during the study period. Two patients who could not return for radiographic evaluation completed questionnaires. The remaining thirty-four patients (thirty-seven hips) were evaluated radiographically and clinically and were followed for an average of forty-one months (range, twenty-four to sixty-six months). RESULTS: Radiographic analysis demonstrated an improvement in the average vertical displacement of the hip center. At the time of the latest follow-up examination, 76 percent (twenty-eight) of the thirty-seven cups were stable, 8 percent (three) were probably unstable with a change in the screw position but no definite migration of the cup, and 16 percent (six) were unstable. Eight of the nine loose or probably loose components were in patients who had more than two centimeters of superior migration of the component and disruption of Kohler's line on preoperative radiographs. Additionally, implants were more likely to become unstable (demonstrating more than 4 degrees of change in the abduction angle or more than four millimeters of radiographic migration) when the inferior aspect of the component did not extend to or distal to the interteardrop line, which indicated that the component was undersized. CONCLUSIONS: On the basis of our early rate of probable or definite loosening of 24 percent (nine of thirty-seven cups) and the technical difficulties involved, we do not recommend the routine use of this component. We believe that this device is indicated when a patient has an oblong-shaped acetabular defect and the surgeon wants to correct an elevated hip center. However, the medial wall of the acetabulum (Kohler's line) should be intact if the failed component has migrated more than two centimeters. An alternative reconstruction technique, such as use of a structural allograft with or without an acetabular cage, is also an option in this situation. 相似文献