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   243953篇
  免费   20028篇
  国内免费   5214篇
耳鼻咽喉   3535篇
儿科学   4316篇
妇产科学   3805篇
基础医学   19100篇
口腔科学   8247篇
临床医学   22061篇
内科学   22112篇
皮肤病学   2620篇
神经病学   11345篇
特种医学   7502篇
外国民族医学   12篇
外科学   32654篇
综合类   38966篇
现状与发展   9篇
一般理论   31篇
预防医学   29940篇
眼科学   3182篇
药学   22827篇
  399篇
中国医学   26995篇
肿瘤学   9537篇
  2024年   1042篇
  2023年   4702篇
  2022年   8865篇
  2021年   11769篇
  2020年   11423篇
  2019年   12395篇
  2018年   11043篇
  2017年   9765篇
  2016年   8951篇
  2015年   8325篇
  2014年   16617篇
  2013年   16782篇
  2012年   14843篇
  2011年   16006篇
  2010年   12902篇
  2009年   11322篇
  2008年   10465篇
  2007年   10641篇
  2006年   9126篇
  2005年   7800篇
  2004年   6507篇
  2003年   5631篇
  2002年   4307篇
  2001年   3621篇
  2000年   3142篇
  1999年   2595篇
  1998年   2052篇
  1997年   1850篇
  1996年   1464篇
  1995年   1391篇
  1994年   1258篇
  1993年   1096篇
  1992年   996篇
  1991年   917篇
  1990年   805篇
  1989年   768篇
  1988年   716篇
  1987年   649篇
  1986年   592篇
  1985年   1857篇
  1984年   2133篇
  1983年   1338篇
  1982年   1782篇
  1981年   1248篇
  1980年   1064篇
  1979年   943篇
  1978年   761篇
  1977年   577篇
  1976年   707篇
  1975年   490篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
急诊抗菌药物的使用调查与分析   总被引:1,自引:0,他引:1  
目的考察了解急诊抗菌药物的使用情况。方法随机抽取2008年7—12月的急诊处方2700张,对其中抗菌药物的应用情况进行统计分析。结果急诊抗菌药物使用率49.1%,药物应用形式以单用为主(占66.3%);给药途径以口服和静脉注射为主。不合理用药处方占抗菌药物处方的10.8%,分别在选药方案、给药方案、溶媒使用、联合应用等方面存在问题。结论我院急诊抗菌药物的应用基本合理,但仍存在一定问题,需进一步加强管理。  相似文献   
82.
83.
Summary We prospectively examined bone growth patterns in 894 children aged 6–17 years at the baseline visit, with a 6-year follow-up. Results show bone “tracking” over a six-year interval and sexual dimorphism of bone attained levels and timing of peak bone growth. Our findings underscore childhood and adolescence as critical periods for building bone and developing gender differences. Introduction Bone growth patterns were prospectively examined in 894 Chinese children (496 males), aged 6–17 yrs, from a population-based twin cohort. Whole-body bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were measured by DEXA at baseline and a 6-yr follow-up. Methods Graphic smoothing plots and generalized estimating equations were used to model bone attained levels, growth, and “tracking”. Results Attained levels of BMC and BA increased curvilinearly with age. Male attained levels were higher than females after age ∼15 yr, but BMD was lower between 13–17 yrs (Tanner stage I to IV). In both genders, peak BMC and BMD growth lagged ∼2 yrs behind peak BA growth, which lagged 2 yrs behind peak height growth. Peak bone growth occurred 1–3 yrs later in males. Over the 6-yr follow-up, all bone measurements “tracked”, but “shifting” across ranks also occurred, and baseline tertile ranking influenced bone growth. Females with early menarche had higher attained levels than females with late menarche at age 12–13 yrs. Conclusion Our findings confirm and expand previous studies on peak bone growth conducted in Caucasian cohorts, particularly sexually dimorphic and maturational effects. The significant “tracking” of bone measurements in this 6-yr follow-up study underscores the importance that osteoporosis prevention should begin in childhood and adolescence. Fengxiu Ouyang and Binyan Wang contributed equally to this article. Source(s) of support: This study is supported in part by grant R01 HD049059, R01 HL0864619 and R01 AR045651 from the National Institute of Health and by the Food Allergy Project.  相似文献   
84.
腰椎后路非融合固定系统的临床应用   总被引:11,自引:1,他引:10  
郑应  谭明生 《中国骨伤》2007,20(4):283-285
复习腰椎后路非融合固定系统的设计原理、临床应用及治疗效果等相关文献,与传统的脊柱融合术相比,应用非融合系统可获得很好的疗效,并可以减少邻近节段退变的发生率。  相似文献   
85.
Diseases like rotavirus afflict both upper- and lower-income countries, but most serious illnesses and deaths occur among the latter. It is a vital public health issue that vaccines for these types of global diseases can recover research and development (R&D) costs from high-priced markets quickly so that manufacturers can offer affordable prices to lower-income nations. Cost recovery depends on how high R&D costs are, and this study attempts to replace high, unverified estimates with lower, more verifiable estimates for two new vaccines, RotaTeq (Merck) and Rotarix (GlaxoSmithKline or GSK), based on detailed searches of public information and follow-up interviews with senior informants. We also offer a new perspective on “cost of capital” as a claim for recovery from public bodies. Our estimates suggest that companies can recover all fixed costs quickly from affluent markets and thus can offer these vaccines to lower-income countries at prices they can afford. Better vaccines are a shared project between companies and public health agencies; greater transparency and consistency in reporting of R&D costs is needed so that fair prices can be established.  相似文献   
86.
距骨骨折的手术治疗   总被引:2,自引:0,他引:2  
目的探讨距骨骨折的特点、类型、手术方法及影响疗效的相关因素。方法1998年12月至2004年12月,共治疗距骨骨折39例,根据Hawkins分型方法,型骨折5例,型骨折25例,型骨折9例。型骨折采用松质骨拉力螺钉内固定;、型骨折行急诊手术,其中型骨折采用前外侧切口暴露,解剖复位,2枚松质骨拉力螺钉交叉内固定;型骨折采用踝前内侧切口暴露,解剖复位,松质骨拉力螺钉内固定,伴有内踝骨折时同时复位内固定,并以自体髂骨块跨骨折线嵌入植骨。术后短腿管形石膏外固定12~24周,X线片示骨折线模糊后拆石膏行不负重下踝关节活动,骨折线消失后恢复伤前活动。结果除2例失访外,37例获得随访。随访时间1.5~6年,平均3年。根据Hawkins疗效标准判定,优12例(32.4%),良17例(45.9%),可6例(16.2%),差2例(5.4%),优良率为78.4%。结论距骨骨折虽然并发症多且后果严重,但是通过急诊手术、解剖复位、有效内固定、自体髂骨块嵌入植骨、局部封闭、理疗等综合治疗,可降低病残率。  相似文献   
87.
We consider nested multiple response models which are used extensively in the area of pharmacometrics. Given the conditional nature of such models, differences in predicted responses are a consequence of different assumptions about how the models interact. As such, sequential versus simultaneous and First Order (FO) versus First Order Conditional Estimation (FOCE) techniques have been explored in the literature where it was found that the sequential and FO approaches can produce biased results. It is therefore of interest to determine any design consequences between the various methods and approximations. As optimal design for nonlinear mixed effects models is dependent upon initial parameter estimates and an approximation to the expected Fisher information matrix, it is necessary to incorporate any influence of nonlinearity (or parameter-effects curvature) into our exploration. Hence, sequential versus simultaneous design with FO and FOCE considerations are compared under low, typical and high degrees of nonlinearity. Additionally, predicted standard errors of parameters are also compared to empirical estimates formed via a simulation/estimation study in NONMEM. Initially, design theory for nested multiple response models is developed and approaches mentioned above are investigated by considering a pharmacokinetic–pharmacodynamic model found in the literature. We consider design for situations where all responses are continuous and extend this methodology to the case where a response may be a discrete random variable. In particular, for a binary response pharmacodynamic model, it is conjectured that such responses will offer little information about all parameters and hence a sequential optimization, in the form of product design optimality, may yield near optimal designs.  相似文献   
88.
The purpose of this study was to assess 7 methods of fixation for a midtarsal osteotomy. Polyurethane foam models (N = 6) and cadaver specimens (N = 4-7) were used to examine the force generated by the different constructs of fixation. A midtarsal osteotomy was performed on each specimen in the test groups. The osteotomies were fixated either with 2 parallel 0.062-in Kirschner wires and 40-mm-long, 4-mm partially threaded, cancellous, cannulated titanium screws, an external ring fixator (frame), a frame with wires tensioned (tension), a frame with wires tensioned and compressed toward the osteotomy (tension and compression), a frame with tension, compression, and parallel Kirschner wires, or a frame with tension, compression, and two 4.0 cannulated parallel screws, respectively. Each model was fixated, and the force generated by the construct across the osteotomy was recorded via the use of pressure-sensitive film. Statistical analysis of the data in the polyurethane foam group determined that the use of frame with tension, compression, and two 4.0 parallel cannulated screws was statistically superior to 1) frame, 2) frame with tension, 3) 2 parallel Kirschner wires, 4) two 4.0 cannulated parallel screws, and 5) frame with tension and compression. A cadaver study determined that the frame with tension, compression, and 2 parallel Kirschner wires was statistically superior to 1) frame and 2) two parallel Kirschner wires. These findings suggest that there is a difference in the force generated by the type of fixation construct across a midtarsal osteotomy.  相似文献   
89.
金军  付伟  钟声 《中国骨伤》2007,20(12):821-822
目的分别应用三针锁针加压器外固定和空心拉力钉内固定疗法治疗股骨颈骨折,探讨股骨颈骨折最佳治疗方法.方法应用三针锁针加压器外固定治疗股骨颈骨折63例,其中男24例,女39例;年龄55~89岁,平均(64.5±3.2)岁;Garderl Ⅰ型2例,Ⅱ型15例,Ⅲ型38例,Ⅳ型8例.应用空心拉力钉内固定治疗63例,其中男29例,女34例;年龄45~76岁,平均(62.2±2.9)岁;Garden Ⅰ型4例,Ⅱ型24例,Ⅲ型28例,Ⅳ型7例.对其疗效进行分析.结果126例除2例死亡外均得到随访.115例愈合,其中10例股骨头坏死.外固定组愈合58例,股骨头坏死4例,死亡1例;内固定组愈合57例,股骨头坏死6例,死亡1例.根据Harris功能评定标准评价疗效,外固定组62例中优24例,良26例,可8例,差4例,优良率80.65%;内固定组62例中优23例,良27例,可6例,差6例,优良率80.65%.Harris评分外固定组平均(80.40±1.21)分,内固定组平均(79.14±1.47)分,两组Harris评分比较差异无统计学意义(P>0.05).结论采用内外固定治疗股骨颈骨折疗效无明显差异,但外固定创伤小、费用低、可早期离床;而采用拉力钉内固定器医疗成本高,卧病时间相对较长,且需二次手术取内固定钉.  相似文献   
90.
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   
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