全文获取类型
收费全文 | 312篇 |
免费 | 29篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 14篇 |
基础医学 | 31篇 |
口腔科学 | 8篇 |
临床医学 | 59篇 |
内科学 | 47篇 |
皮肤病学 | 11篇 |
神经病学 | 76篇 |
特种医学 | 22篇 |
外科学 | 23篇 |
综合类 | 9篇 |
预防医学 | 13篇 |
眼科学 | 14篇 |
药学 | 51篇 |
中国医学 | 1篇 |
肿瘤学 | 11篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 17篇 |
2011年 | 12篇 |
2010年 | 18篇 |
2009年 | 17篇 |
2008年 | 14篇 |
2007年 | 42篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有392条查询结果,搜索用时 15 毫秒
41.
42.
HY Chan XQ Yao SY Tsang BP Bourreau FL Chan Y Huang . 《Journal of cardiac surgery》2002,17(6):562-562
Background: Calcitonin gene-related peptide (CGRP) is known to have an extremely potent and prolonged vasodilator effect on the coronary arteries. Studies have shown that CGRP increased coronary blood flow and alleviated reperfusion injury in vitro. It is still unknown, however, whether exogenous CGRP has a protective effect on the reperfusion heart associated with cardiopulmonary bypass (CPB). Methods: An in vivo porcine model of CPB was established. Twenty pigs, 10 controls and 10 CGRP used animals (CGRP group), were performed a median sternotomy followed by a standard CPB. All the hearts were arrested for 45 minutes. In the CGRP group, 1mg/kg CGRP was added into the cardioplegia, and another 1mg/kg was reperfused just before the aortic cross-clamp was removed. In both groups, myocardial microvascular perfusion, coronary arterial microvessel diameter and microvessel blood flow were detected by a laser doppler flowmeter and a contact microscope with TV monitor on five consecutive time perioperatively. Result: Myocardial microvascular perfusion was significantly higher and coronary arterial microvessel diameter was larger in the CGRP group on every point of time of reperfusion compared to those in the control group. In the CGRP group, microvessel blood flow also improved significantly than that in the control group during reperfusion. Conclusion: CGRP improves myocardial microcirculation during cardiac ischemia-reperfusion associated with CPB and could become a new, potent myocardial protector. 相似文献
43.
Agnes Tiwari Marie Tarrant Kwan Hok Yuen Sophia Chan Sarah Kagan Patricia Ching Alan Wong Samson SY Wong 《Journal of nursing scholarship》2006,38(4):308-313
BACKGROUND: To present preparedness planning for an influenza pandemic for two nursing subunits: nursing services in hospitals and schools of nursing in universities. DISCUSSION: The preparedness plan is modeled on a modified Haddon matrix, a logical approach to identify measures appropriate for the pre-event, event, and postevent phases of an influenza pandemic. For the pre-event phase, the objective is to ensure preparedness for the potential pandemic outbreak through training, communication, surveillance, infection control, and vaccination. Once the pandemic outbreak is declared, the aim is to implement effective measures to ensure a rapid and appropriate response. For the postevent phase, the plan is focused on the restoration of core functions, vigilance for a second or possibly more waves of the pandemic, and psychosocial support to staff and students. CONCLUSION: Measures required to prepare for, respond to, and manage the consequences of influenza pandemic are identified. This planning indicates the need to balance a logical approach with contextual perspectives and the importance for nursing leaders to develop plans for subunits of larger entities. 相似文献
44.
Bernard MY Cheung THY Au SY Chan CM Lam SH Lau RP Lee SF Lee WS Lo EHF Sin MY Tang HH Tsang 《Experimental & Clinical Cardiology》2005,10(1):21-24
BACKGROUND:
Psychosocial stress can be the cause or the consequence of hypertension.OBJECTIVE:
To study the association between hypertension and anxiety or depression in adults from Hong Kong, China.SUBJECTS AND METHODS:
Patients with diagnosed hypertension (n=197) were recruited to complete the Hospital Anxiety and Depression Scale (HADS) questionnaire. The control group comprised 182 normotensive subjects recruited using random telephone numbers.RESULTS:
The score in the anxiety subscale (HADS-A) of the HADS correlated with age (r= −0.23, P<0.001) and sex (r=0.11, P=0.042), and was found to be higher in women. The score in the depression subscale (HADS-D) correlated with age (r=0.17, P=0.003) and hypertension (r=0.12, P=0.039), but not with sex (r=0.02, P=0.68). When the control subjects were matched for sex and age with the subjects with hypertension, the mean HADS-A score was 5.51±0.41 in 113 hypertensive subjects and 4.38±0.39 in 113 normotensive subjects (P=0.047). The mean HADS-D score was 5.56±0.39 in the hypertensive and 4.76±0.32 in the normotensive subjects (P=0.11). Multiple regression analysis using data from both groups indicated that the HADS-A score was related to the HADS-D score (β=0.49, P<0.001), age (β= −0.25, P<0.001) and sex (β=0.12, P=0.01) (R2=0.28), whereas the HADS-D score was related to the HADS-A score (β=0.48, P<0.001), age (β=0.30, P<0.001), positive smoking status (β=0.13, P=0.004) and lack of exercise habit (β=0.12, P=0.008) (R2=0.31). Hypertension was related to waist circumference, history of parental hypertension and age (R2=0.38, P<0.001). Anxiety and depression scores were rejected as independent variables.CONCLUSIONS:
Hypertension was associated with anxiety but not depression; however, age, history of parental hypertension and central obesity appeared to have a stronger association with hypertension in adults from Hong Kong. 相似文献45.
Zhang SY; Zhu J; Chen GQ; Du XX; Lu LJ; Zhang Z; Zhong HJ; Chen HR; Wang ZY; Berger R; Lanotte M; Waxman S; Chen Z; Chen SJ 《Blood》1996,87(8):3404-3409
Acute promyelocytic leukemia (APL) is an interesting model for cancer research because of the presence of the specific PML-RARalpha fusion gene associated with the clinical response to retinoic acid differentiation therapy. To better understand and improve differentiation induction with retinoic acid, we have established a human APL-ascites model in SCID mice using the NB4 human APL cell line. NB4 (1 x 10(6) cells) were transplanted into the peritoneum (IP) of SCID mice for 1 month. NB4 ascites cells (A-NB4) appeared, which were then engrafted in SCID mice periodically for 18 passages at an interval of 3 to 4 weeks with a 100% success rate of tumor induction. The mean survival times of SCID mice transplanted with 1 x 10(6) A-NB4 cells was 21.6 +/- 2.3 days. Analysis of the biologic characteristics of ninth passage NB4 ascitic cells was performed and they were found to have the morphologic, immunologic, cytogenetic, and molecular features of cultured NB4 cells. Furthermore, A-NB4 cells were capable of differentiating when treated with all-trans retinoic acid (ATRA), as manifested by enhanced NBT reduction and CD11b expression. In vivo treatment with ATRA in SCID mice for 4 days also increased NBT reduction by A-NB4 cells. ATRA treatment significantly prolonged survival time in the group after transplantation (28.1 +/- 6.8 to 29.1 +/- 8.4 days) compared with the control (P < .001). Furthermore, treatment with adriamycin, an effective chemotherapeutic drug in APL, had a strong growth suppressive effect on A-NB4 cells. These results demonstrate that this SCID-APL (NB4 ascites cells) model is a useful preclinical system for evaluating new or known drugs in the treatment of APL. 相似文献
46.
紫外分光光度法测定复方酮康唑软膏中酮康唑和氧氟沙星的含量 总被引:4,自引:0,他引:4
目的:建立复方酮康唑软膏的含量测定方法。方法:用双波长分光光度法测定酮康唑的含量,用单波长法测定氧氟沙星的含量。结果:两被测组分的平均回收率和相对标准偏差分别为酮康唑100.33%和0.32%;氧氟沙星100.85%和0.27%。结论:方法简便、准确,可用于复方酮康唑软膏的质量控制。 相似文献
47.
E. LACASSIE A. DELMAS C. MEUNIER D. SY Y. TRUDELLE 《Chemical biology & drug design》1996,48(3):249-258
An amphipathic polypeptide, Pn, with a tandemly repeated LKELPEKL sequence including a proline every eight residues, as well as a series of shorter peptides having the same sequence, P2, P3, P4, P5 and P6, were synthesized. Their conformation in aqueous solution was mainly studied by CD. At low temperature, these peptides and polypeptide are completely unordered and undergo a reversible transition leading to a partly α-helical structure upon heating. Such behavior has been demonstrated for a few proteins by other authors and has been called cold-denaturation. The transition temperature of the polypeptide is close to 20 ° C. The conformational change does not depend on concentration, indicating a monomolecular process. The high-temperature structure seems to be compact as for globular proteins. A model of folded structure is proposed from experimental data and from molecular modelling studies. © Munksgaard 1996. 相似文献
48.
The elbow: MR features of nerve disorders 总被引:3,自引:0,他引:3
49.
Susan Y. Bookheimer Thomas A. Zeffiro Teresa Blaxton William Gaillard William Theodore 《Human brain mapping》1995,3(2):93-106
By several accounts, reading single words may be accomplished either by sequentially transcribing orthographic units into their corresponding sounds (an indirect route), or by directly associating a visual word form to the semantic or articulatory representation (a direct route). By contrast, the similar task of naming objects must rely only on a direct route, since objects cannot be “sounded out.” To study the localization of cognitive processes specific to reading, we used positron emission tomography (PET) to measure regional cerebral blood flow while subjects named words and pictures of objects silently or aloud. Group averages of blood flow changes were obtained for experimental vs. control tasks. Object and word presentations elicited similar blood flow increases in extra-striate visual cortices compared with a visual noise control. Silent reading invoked a neural network very similar to that seen when subjects named objects silently, consistent with a “direct” route. Naming objects aloud produced the addition of motor output regions to this network. By contrast, oral reading produced a markedly different pattern of activated regions, suggesting reliance on a separate phonological pathway. These results provide support for the dual coding hypothesis in reading and challenge the use of strict hierarchical models of cognitive operations in PET activation studies. © 1995 Wiley-Liss, Inc. 相似文献
50.
Alternating poly(Glu-Leu) was synthesized by the condensation of the corresponding dipeptide p-nitrophenyl ester at high concentration. It exhibits a random coil structure in pure water at neutral pH. Addition of monovalent cations, such as NH+4 to a final 0.1 M solution, induces a transition to a water soluble β-structure. The salt effect is quite selective since no transition was observed with Li+, Na+ or Cs+ ions. Addition of 0.5 equiv. of calcium, cobalt or manganese chlorides per glutamyl residue induces similar coil to β-sheet transitions. No polymer precipitation was observed at these very low salt concentrations. Addition of 0.5 equiv. of Cu2+ or 0.15 equiv. of Fe3+ induces a coil to α-helix transition. Molecular modeling has been used to understand tentatively the main factors controlling the different conformations observed with the various metal ions. © Munksgaard 1997. 相似文献