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   235124篇
  免费   20624篇
  国内免费   5401篇
耳鼻咽喉   3574篇
儿科学   4383篇
妇产科学   3669篇
基础医学   17635篇
口腔科学   7701篇
临床医学   27681篇
内科学   22679篇
皮肤病学   2450篇
神经病学   12298篇
特种医学   6063篇
外国民族医学   13篇
外科学   21842篇
综合类   36228篇
现状与发展   13篇
一般理论   32篇
预防医学   33948篇
眼科学   2205篇
药学   21917篇
  421篇
中国医学   26970篇
肿瘤学   9427篇
  2024年   1077篇
  2023年   4810篇
  2022年   8934篇
  2021年   11839篇
  2020年   11669篇
  2019年   12882篇
  2018年   11264篇
  2017年   9811篇
  2016年   8831篇
  2015年   8222篇
  2014年   16024篇
  2013年   17128篇
  2012年   14125篇
  2011年   15059篇
  2010年   12184篇
  2009年   10518篇
  2008年   9805篇
  2007年   9990篇
  2006年   8442篇
  2005年   7065篇
  2004年   5851篇
  2003年   5273篇
  2002年   4082篇
  2001年   3414篇
  2000年   3005篇
  1999年   2446篇
  1998年   1942篇
  1997年   1736篇
  1996年   1409篇
  1995年   1318篇
  1994年   1195篇
  1993年   1060篇
  1992年   959篇
  1991年   874篇
  1990年   761篇
  1989年   713篇
  1988年   662篇
  1987年   598篇
  1986年   548篇
  1985年   1805篇
  1984年   2070篇
  1983年   1299篇
  1982年   1728篇
  1981年   1195篇
  1980年   1024篇
  1979年   911篇
  1978年   741篇
  1977年   557篇
  1976年   699篇
  1975年   481篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
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   
22.
23.
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   
24.
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   
25.
AIMS: The aim of this study is to compare PUMA curves with different pathologic conditions causing bladder dysfunction in 158 men and 83 women. METHODS: PUMA results in terms of bladder outlet obstruction and detrusor contractility were compared in 92 men with benign prostatic hypertrophy (BPH) and p(ves) congruent with p(det) (i.e., p(abd) congruent with 0) with the results of the urodynamics operator's opinion, the provisional International Continence Society method, Abrams and Griffith's diagram, urethral resistence factor (URA), Sch?fer's diagram, and Watt factor. PUMA curves correlated reliably with different pathologic conditions such as obstructive BPH, orthotopic bladder, cystocele, the neurological bladder, and bladder diverticulum. Statistical analysis indicated excellent agreement between PUMA and URA; agreement with other methods was good in cases of obstruction and nonobstruction. In doubtful cases, as diagnosed by standard methods, PUMA agreed only with the Abrams and Griffith's diagram. PUMA and Wmax were in good agreement on detrusor con traction force. Agreement between PUMA and Sch?fer's diagram was excellent for patients with detrusor hypercontractility and good for patients with detrusor hypocontractility and normocontractility. PUMA is the only method applicable to women. It is easy to perform. When integrated with other diagnostic tests, it provides realistic data for diagnosis, medical or surgical therapy, and outcome.  相似文献   
26.
In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished.  相似文献   
27.
中风毒邪论是一种与传统中医中风病理有所不同的理论 ,在中风毒邪论指导下形成解毒通络方是较为理想的神经保护剂 ,可解决目前神经保护治疗的主要障碍 ,有望成为提高中医治疗中风急性期疗效的关键  相似文献   
28.
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups.  相似文献   
29.
大学新生心理健康状况的调查研究   总被引:2,自引:0,他引:2  
目的 了解大学新生的心理健康状况 ,探讨提高其心理健康水平的措施。方法 采用大学生人格问卷(UPI) ,以班级为单位 ,在新生正式上课两周以后进行测试。结果 学生一类筛选率 9.2 4 %。UPI关键题选择中 ,以常常失眠占的比例最高 ,想轻生的比例最低 (P <0 .0 5 )。UPI附加题选择中 ,以自身健康方面有问题及有健康或心理卫生方面想要咨询的问题较多 (P <0 .0 5 )。选择“想轻生”的男生的比例略高于女生 ,选择“常常失眠”的女生的比例却明显高于男生 (P <0 .0 5 ) ;选择“常常失眠”、“对任何事情都不感兴趣”和“感觉自己的过去及家庭不幸”的农村学生的比例都高于城市学生 (P <0 .0 5 )。选择“想轻生”和“对任何事情都不感兴趣”的独生子女的比例明显高于非独生子女 ,而选择“自己的过去和家庭是不行的”和“常常失眠”的非独生子女的比例又明显高于独生子女 (P <0 .0 5 )。结论 单亲家庭学生、残疾学生、家庭经济困难学生、独生子女学生是心理问题高危人群  相似文献   
30.
The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available.  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