全文获取类型
收费全文 | 9122篇 |
免费 | 476篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 140篇 |
儿科学 | 407篇 |
妇产科学 | 62篇 |
基础医学 | 1068篇 |
口腔科学 | 229篇 |
临床医学 | 633篇 |
内科学 | 2013篇 |
皮肤病学 | 244篇 |
神经病学 | 777篇 |
特种医学 | 193篇 |
外科学 | 1483篇 |
综合类 | 195篇 |
一般理论 | 1篇 |
预防医学 | 435篇 |
眼科学 | 263篇 |
药学 | 732篇 |
1篇 | |
中国医学 | 24篇 |
肿瘤学 | 728篇 |
出版年
2023年 | 73篇 |
2022年 | 142篇 |
2021年 | 295篇 |
2020年 | 151篇 |
2019年 | 227篇 |
2018年 | 296篇 |
2017年 | 203篇 |
2016年 | 240篇 |
2015年 | 275篇 |
2014年 | 397篇 |
2013年 | 504篇 |
2012年 | 766篇 |
2011年 | 800篇 |
2010年 | 411篇 |
2009年 | 362篇 |
2008年 | 557篇 |
2007年 | 553篇 |
2006年 | 552篇 |
2005年 | 494篇 |
2004年 | 442篇 |
2003年 | 427篇 |
2002年 | 348篇 |
2001年 | 137篇 |
2000年 | 121篇 |
1999年 | 113篇 |
1998年 | 59篇 |
1997年 | 54篇 |
1996年 | 45篇 |
1995年 | 19篇 |
1994年 | 28篇 |
1993年 | 38篇 |
1992年 | 60篇 |
1991年 | 59篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 34篇 |
1987年 | 38篇 |
1986年 | 27篇 |
1985年 | 29篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1975年 | 10篇 |
1972年 | 5篇 |
1970年 | 5篇 |
1967年 | 6篇 |
排序方式: 共有9628条查询结果,搜索用时 15 毫秒
71.
Herbal remedies have become popular, due in part to the lower risk of adverse reactions. Thousands of plants have been used traditionally to treat various diseases. Among them, species of the genus Piper are important medicinal plants used in various systems of medicine. The Piper longum fruit has been used in traditional medicine, including the Ayurvedic system of medicine. Although there are numerous indications for its use, controlled trials are needed to determine its efficacy. The primary constituents isolated from various parts of P. longum are piperine, piperlongumine, sylvatin, sesamin, diaeudesmin piperlonguminine, pipermonaline, and piperundecalidine. It is most commonly used to treat chronic bronchitis, asthma, constipation, gonorrhea, paralysis of the tongue, diarrhea, cholera, chronic malaria, viral hepatitis, respiratory infections, stomachache, bronchitis, diseases of the spleen, cough, and tumors. This study provides detailed information about the P. longum fruit, including phytochemistry, pharmacological profile and safety profile. In view of the commercial, economic, and medicinal importance of the P. longum plant, it is useful for researchers to study the plant in detail. 相似文献
72.
73.
Current status of DNA vaccines in veterinary medicine 总被引:14,自引:0,他引:14
Krishnan BR 《Advanced drug delivery reviews》2000,43(1):3-11
DNA vaccination entails administration of the DNA itself encoding antigen to direct synthesis of the antigen directly in the target organism. The target organism's immune system recognizes the antigen, and generates humoral (antibody)- and/or cell-mediated immune response. DNA vaccines afford numerous advantages over conventional vaccines, including ease of production, stability and transport. They overcome the need to cultivate dangerous infectious agents, and provide a possibility to vaccinate against multiple pathogens in a single shot. DNA vaccination is beginning to be explored for many pathogens of veterinary interest. The status of DNA vaccines in poultry, livestock and companion animals is reviewed here. While examples of DNA vaccines being tested in the veterinary field are not numerous, the early studies highlight the potential DNA vaccinology offers in veterinary medicine. 相似文献
74.
Shoba Krishnan Srikantan Robert A Berg Tim Cox Lisa Tice Vinay M Nadkarni 《Pediatric critical care medicine》2005,6(3):293-297
OBJECTIVE: Optimal chest compression to ventilation ratio (C:V) for one-rescuer cardiopulmonary resuscitation (CPR) is not known, with current American Heart Association recommendations 3:1 for newborns, 5:1 for children, and 15:2 for adults. C:V ratios influence effectiveness of CPR, but memorizing different ratios is educationally cumbersome. We hypothesized that a 10:2 ratio might provide adequate universal application for all age arrest victims. DESIGN: Clinical study. SETTING: Tertiary care children's hospital. SUBJECTS: Thirty-five health care providers. INTERVENTIONS: Thirty-five health care providers performed 5-min epochs of one-rescuer CPR at C:V ratios of 3:1, 5:1, 10:2, and 15:2 in random order on infant, pediatric, and adult manikins. Compressions were paced at 100/min by metronome. The number of effective compressions and ventilations delivered per minute was recorded by a trained basic life support instructor. Subjective assessments of fatigue (self-report) and exertion (change in rescuer pulse rate compared with baseline) were assessed. Analysis was by repeated measures analysis of variance and paired Student's t-test. MEASUREMENTS AND MAIN RESULTS: Effective infant compressions per minute did not differ by C:V ratio, but ventilations per minute were greater at 3:1 vs. 5:1, 10:2, and 15:2 (p < .05). Effective pediatric compressions per minute were less at 3:1 vs. 5:1, 10:2, and 15:2 (p < .05) and not different between 5:1, 10:2, and 15:2 ratios. Effective pediatric ventilations per minute were greater at 3:1 than all other ratios and both 5:1 and 10:2 were >15:2 (p < .05). Effective adult compressions per minute were progressively greater with 3:1 vs. 5:1 vs. 10:2 vs. 15:2 (p < .05). Self-efficacy was assessed, and rescuers always subjectively rated 10:2 and 15:2 ratios as easier than 5:1 or 3:1 ratios for all manikins. Rescuer pulse change (exertion) was greater after pediatric and adult vs. infant CPR (p < .05), with no significant difference by C:V ratio. CONCLUSIONS: C:V ratio and manikin size have a significant influence on the number of effective compressions and ventilations delivered during ideal, metronome-paced, one-rescuer CPR. Low ratios of 3:1, 5:1, and 10:2 favor ventilation, and high ratios of 15:2 favor compression, especially in adult manikins. Rescuers subjectively preferred C:V ratios of 10:2 and 15:2 over 3:1 or 5:1. Infant CPR caused less exertion and subjective fatigue than pediatric or adult CPR technique, without significant difference by C:V ratio. We speculate that a universal 10:2 C:V ratio for one-rescuer layperson CPR is physiologically reasonable but warrants further study with particular attention to educational value and technique retention. 相似文献
75.
76.
77.
Omar SZ Qvist R Khaing SL Muniandy S Bhalla S 《The journal of obstetrics and gynaecology research》2008,34(2):174-178
AIM: The aim of the present study was to determine the existence or prevalence of thrombophilic markers such as Factor V Leiden, prothrombin G20210A, protein S, protein C, activated protein C and anti-thrombin in pre-eclampsia and pregnancy-induced hypertensive patients. METHODS: Blood samples were collected from a total number of 124 women at the maternity unit, University of Malaya Medical Center. These included 49 patients with pre-eclampsia, 63 patients with pregnancy-induced hypertension and 12 normal pregnant women. DNA was extracted from the blood samples. Factor V Leiden (Taq I) and prothrombin G20210A (Hind III) genotyping was done on polymerase chain reaction-restriction fragment length polymorphism. Anti-thrombin activity and the concentrations of protein C, protein S and activated protein C were measured using the IL Coagulation System (Hemosil). RESULTS: Of the 124 subjects, one pre-eclampsia patient was homozygous for Factor V Leiden mutation but prothrombin G20210A mutation was not present in any of the subjects. The subject with Factor V Leiden mutation also had a low activated protein C resistance and a low protein S concentration. CONCLUSIONS: Factor V Leiden mutation is present in the Asian population and may very well serve as one of the genetic factors responsible for pre-eclampsia and other adverse pregnancy outcomes. 相似文献
78.
Kumar S Malhotra N Chumber S Gupta P Aruna J Roy KK Sharma JB 《Archives of gynecology and obstetrics》2007,276(4):385-386
Background Massive life threatening bleeding from presacral venous plexus in gynecological surgery, though uncommon can be fatal when
conventional methods fail.
Case In the present case, a 55-year-old woman undergoing radical hysterectomy for cancer cervix was saved using thumbtacks to control
bleeding from presacral vessels when conventional methods were ineffective.
Conclusion Use of thumbtacks in such patients is simple, cost effective and life saving. 相似文献
79.
Age and sex effects on brain morphology 总被引:6,自引:0,他引:6
Theodore J. Passe Pradeep Rajagopalan Larry A. Tupler Christopher E. Byrum James R. Macfall K.Ranga Rama Krishnan 《Progress in neuro-psychopharmacology & biological psychiatry》1997,21(8):1231-1237
- 1. 1. Brain morphology can be assessed readily in vivo using magnetic resonance imaging (MRI).
- 2. 2. In this study, the effects of age and sex on whole-brain morphology were examined using an operator-controlled computer-segmentation protocol.
- 3. 3. Results indicated that age was associated with gray-matter volume reduction.
- 4. 4. Brain-size differences between males and females were primarily attributable to whitematter volume.
- 5. 5. This study confirms the importance of controlling for age and sex in brain-morphology studies.
80.