全文获取类型
收费全文 | 18274篇 |
免费 | 1597篇 |
国内免费 | 634篇 |
专业分类
耳鼻咽喉 | 271篇 |
儿科学 | 109篇 |
妇产科学 | 117篇 |
基础医学 | 1334篇 |
口腔科学 | 1347篇 |
临床医学 | 1506篇 |
内科学 | 1164篇 |
皮肤病学 | 51篇 |
神经病学 | 803篇 |
特种医学 | 1034篇 |
外科学 | 1510篇 |
综合类 | 2512篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 2411篇 |
眼科学 | 164篇 |
药学 | 3919篇 |
21篇 | |
中国医学 | 1910篇 |
肿瘤学 | 317篇 |
出版年
2024年 | 52篇 |
2023年 | 362篇 |
2022年 | 653篇 |
2021年 | 807篇 |
2020年 | 708篇 |
2019年 | 682篇 |
2018年 | 680篇 |
2017年 | 696篇 |
2016年 | 688篇 |
2015年 | 734篇 |
2014年 | 1173篇 |
2013年 | 1723篇 |
2012年 | 1169篇 |
2011年 | 1239篇 |
2010年 | 927篇 |
2009年 | 945篇 |
2008年 | 1004篇 |
2007年 | 928篇 |
2006年 | 800篇 |
2005年 | 707篇 |
2004年 | 519篇 |
2003年 | 465篇 |
2002年 | 403篇 |
2001年 | 356篇 |
2000年 | 290篇 |
1999年 | 233篇 |
1998年 | 179篇 |
1997年 | 175篇 |
1996年 | 145篇 |
1995年 | 121篇 |
1994年 | 121篇 |
1993年 | 103篇 |
1992年 | 96篇 |
1991年 | 68篇 |
1990年 | 52篇 |
1989年 | 57篇 |
1988年 | 59篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 44篇 |
1984年 | 43篇 |
1983年 | 22篇 |
1982年 | 34篇 |
1981年 | 26篇 |
1980年 | 31篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 19篇 |
1976年 | 18篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
本文定义了一类“近乎双线性”系统。可用以近似一类奇异摄动双线性系统,而且可以描述某些实际工业对象。并发现其控制器的设计较方便。文中还给出了一种简单的反馈控制器的设计方法。又对一类多输入双线性系统,提出一种设计反馈控制器的改进方案,根据Lyapunov定理得到一非线性反馈控制律。以上设计方法分别对某合成氨反应器作了应用研究,仿真结果表明了方法的有效性。 相似文献
102.
目的 评价金茵利胆胶囊的体外抗炎活性,并研究其抗炎谱效关系。方法 建立LPS诱导的RAW264.7细胞炎症模型,通过检测细胞上清中NO、TNF-α和IL-6等指标的含量来评价金茵利胆胶囊的抗炎活性。在此基础上,采用均匀设计法制备金茵利胆胶囊组成饮片的不同配伍样本,采用高效液相法建立均匀设计样品的指纹图谱,对均匀设计样品进行抗炎活性测定;以细胞上清液中NO、TNF-α和IL-6的抑制率为药效指标,与共有峰峰面积经灰色关联分析构建抗炎谱效关系。结果 金茵利胆胶囊提取物(0.25~1.00 mg/mL)能显著降低LPS诱导的RAW264.7细胞分泌NO、TNF-α和IL-6。经对照品比对指认出其中7个色谱峰,分别为新绿原酸(9号峰)、绿原酸(13号峰)、隐绿原酸(14号峰)、1, 3-二咖啡酰奎宁酸(16号峰)、对羟基苯乙酮(17 号峰)、柚皮苷(21 号峰)、新橙皮苷(23 号峰)。抗炎谱效关系结果表明,共有峰均具有一定的抗炎贡献度,其中共有峰峰21(柚皮苷)、峰23(新橙皮苷)与3个细胞炎症指标的关联度均大于0.74。结论:金茵利胆胶囊发挥抗炎作用是多种成分共同作用的结果,为金茵利胆胶囊抗炎药效物质基础及其质量控制提升提供参考。 相似文献
103.
Ann Netten 《International journal of geriatric psychiatry》1989,4(3):143-153
A study of 13 homes for elderly people examining the effect of the environment on demented residents looked into the complexity of the design from the residents' point of view. Two principal tools were used in this investigation: ‘route diagrams’, which describe a resident's use of the home, and a measure devised to indicate each resident's ability to find her way around the home. These are described and the relationship between them explored. From this the following tentative conclusions are drawn:
- (i) The variables that influence a resident's ability to find her way around differ between group and communally designed homes.
- (ii) It would appear that group homes provide a more favourable design, especially in the case of physically frail demented elderly people.
- (iii) In group homes, the level of lighting is an important aid to a demented person in finding her way around.
- (iv) In communal homes, residents seem most able to find their way around homes that have been adapted from older premises.
- (v) In both types of home, ‘meaningful decision points’ can be seen as aids to a resident finding her way around.
104.
Chien Yie W. Chien Te-yen Bagdon Robert E. Huang Yih C. Bierman Robert H. 《Pharmaceutical research》1989,6(12):1000-1010
Several transdermal contraceptive device (TCD) formulations were developed to provide a dual-controlled transdermal delivery of levonorgestrel (LN), a potent progestin, and 17-estradiol (E2), a natural estrogen. Using a sensitive HPLC method, the in vitro release and skin permeation profiles of LN and E2 from various TCD formulations were simultaneously characterized in the hydrodynamically well-calibrated Valia–Chien skin permeation cells and both were found to follow zero-order kinetics. The rates of drug release and skin permeation were observed to vary significantly depending upon some formulation parameters. Six-month stability studies were performed on seven formulations at room and elevated temperatures (37 and 45°C), and two (Formulations 4 and 5) were found to be acceptable, based on drug recovery, release rate, and skin permeation rate data. Judging from the 6-month accelerated stability studies, it is projected these two formulations will have shelf-life of at least 2 years. As a result of development of an efficient manufacturing process, Formulation 4 was selected for further evaluation. One-week primary skin irritation evaluation in 6 rabbits indicated that Formulation 4 is nonirritating, and it was thus selected for Phase I clinical bioavailability/dose proportionality studies in 12 healthy female volunteers of child-bearing age. Results of pharmacokinetic and pharmacodynamic analyses demonstrated that it is capable of achieving and maintaining a steady-state serum level of LN throughout the 3-week treatment period by weekly applications of one or two TCD patches (10 or 20 cm2). A dose proportionality was obtained in the serum drug levels, daily dose delivered, and contraception efficacy. An excellent correlation was obtained for the rates of transdermal delivery determined by the in vitro studies using human cadaver skin, the in vivo studies in rabbits, and the clinical studies in living subjects. 相似文献
105.
Lai J Gouldstone A Butler JP Federspiel WJ Loring SH 《Respiratory physiology & neurobiology》2002,131(3):233-243
The pleural space is modeled in two dimensions as a thin layer of fluid separating a deformable membrane and a rigid surface containing a bump. We computed the steady-state membrane configuration and fluid pressure distribution during relative sliding of the two surfaces. For physiologically relevant values of membrane tension, shear flow-induced pressures near the bump and far-field pressure gradients are similar to those measured in vivo within the pleural space (e.g. Lai-Fook et al.) [J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 56 (1984) 1633-1639]. Deformation of the membrane over the bump suggests that the pressure field generated by the sliding motion promotes an even layer of fluid in the pleural space, preventing asperities from touching. Results also suggest a possible mechanism for pleural fluid redistribution during breathing, whereby irreversible fluid motion is associated with the deformability of the membrane. 相似文献
106.
Marina Rova Claire Burrell Marika Cohen 《Body, Movement and Dance in Psychotherapy: An International Journal for Theory, Research and Practice》2020,15(3):204-218
ABSTRACT In this reflective article we introduce Moving Space, a creative movement and art project supporting female Asylum Seekers as they move through the transient space of temporary accommodation. We explore how this cross-modal approach supports women to anchor experiences of displacement, loss and trauma through the use of embodied and visual creative process. Moreover, we argue that the transient nature of the therapeutic space brings into focus women’s resourcefulness and resilience despite the adversity and uncertainty they are experiencing. 相似文献
107.
Maitrot A Lucas MF Doncarli C Farina D 《Medical & biological engineering & computing》2005,43(4):487-492
In the study, an efficient method to perform supervised classification of surface electromyogram (EMG) signals is proposed.
The method is based on the choice of a relevant representation space and its optimisation with respect to a training set.
As EMG signals are the summation of compact-support waveforms (the motor unit action potentials), a natural tool for their
representation is the discrete dyadic wavelet transform. The feature space was thus built from the marginals of a discrete
wavelet decomposition. The mother wavelet was designed to minimise the probability of classification error estimated on the
learning set (supervised classification). As a representative example, the method was applied to simulate surface EMG signals
generated by motor units with different degrees of short-term synchronisation. The proposed approach was able to distinguish
surface EMG signals with degrees of synchronisation that differed by 10%, with a misclassification rate of 8%. The performance
of a spectral-based classification (error rate approximately 33%) and of the classification with Daubechies wavelet (21%)
was significantly poorer than with the proposed wavelet optimisation. The method can be used for a number of different application
fields of surface EMG classification, as the feature space is adapted to the characteristics of the signal that discriminate
between classes.
An erratum to this article is available at . 相似文献
108.
Gillian Rice Jenny Ingram Jacques Mizan 《The British journal of general practice》2008,58(552):465-470
BACKGROUND: Few studies have examined the effect on patients and staff of the physical environment in primary care facilities. AIM: To explore changes in patient and staff satisfaction, patient anxiety, and patient-doctor communication when a GP surgery moves from old premises to enhanced purpose-built accommodation. DESIGN OF STUDY: Questionnaire surveys, interviews, and focus groups pre- and post move. SETTING: An urban general practice in Bristol. METHOD: Patient questionnaires assessed anxiety (Spielberger State-Trait Anxiety Inventory; STAI), satisfaction with the environment, and communication during the consultation. Staff questionnaires assessed satisfaction with the environment and job satisfaction. Qualitative methods explored patient and staff views in more depth. RESULTS: A total of 1118 pre-move and 954 post-move patient questionnaires showed significant increases in satisfaction scores for reception/waiting areas (mean 6.46, 95% confidence interval [CI]=5.97 to 6.95) and consulting rooms (mean 3.80, 95% CI=3.44 to 4.15) in the new premises. Patients' satisfaction with patient-doctor communication also increased (mean 0.88, 95% CI=0.30 to 1.46) and anxiety scores were significantly reduced before and after the consultation in the new premises compared with the old (STAI mean difference before consultation 0.72, 95% CI=0.37 to 1.08; mean after consultation 0.37, 95% CI=0.03 to 0.72). Patients highlighted the increased space and light, more modern appearance, greater comfort, and novel works of art in the new surgery. Staff workplace satisfaction increased significantly after moving and remained higher than in the old building. CONCLUSION: This large-scale study examining the effects of a UK primary care environment on patients and staff shows that an enhanced environment is associated with improvements in patients' perception of patient-doctor communication, reduction in anxiety, and increases in patient and staff satisfaction. 相似文献
109.
The effects of imidacloprid (Advantage) on sheep keds (Melophagus ovinus Linné 1758) were studied in vivo and in vitro by means of direct observation (monitored on video tape) and by light and electron
microscopy. It was found that:
1. Imidacloprid acted rapidly on all motile stages of the sheep keds. Within 3–4 min after exposure they became immobile and
their legs and the abdomen started tetanic trembling movements for 15–30 min, leading to death.
2. The compound is apparently taken up by the body, since it also acted on those sheep keds that had been exclusively exposed
to imidacloprid-contaminated filter papers.
3. The compound is available and active for more than 1 month in the wool of sheep; even rainfall does not reduce its efficacy.
Body contact between treated mother sheep and their lambs protects them from infestation with these ectoparasites.
4. The compound initiates an ultimately lethal destruction of the ganglia, nerve chords and related muscle fibers, as can
be seen in electron micrographs.
Received: 7 October 2000 / Accepted: 18 October 2000 相似文献
110.
G. D. Tansley R. J. Edwards C. R. Gentie 《Medical & biological engineering & computing》1988,26(2):175-185
The paper aims to present the strengths and weaknesses of computational fluid mechanics (CFM) compared with existing in vitro
haemodynamic techniques such as LDA, hot-wire anemometry and static pressure measurement, and to discuss the application of
CFM to the analysis of prosthetic heart valve flow. It presents a brief summary of existing methods used in analysing in vitro
heart valve flow (along with CFM), the special problems inherent in each method and the quantities each is capable of giving.
The analysis then goes on to present examples of information yielded by CFM. It also contains a brief discussion of the data
requirements for the analysis of heart valve performance and the clinical relevance of fluid dynamic occurrences. The conclusion
drawn is that CFM has a major role to play in the analysis of prosthetic heart valve flow and design because of the improved
availability of data afforded and the increased correlation between CFM and clinical flow regimes, due to the ability to consider
realistic models of blood. 相似文献