全文获取类型
收费全文 | 913篇 |
免费 | 70篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 53篇 |
妇产科学 | 45篇 |
基础医学 | 100篇 |
口腔科学 | 18篇 |
临床医学 | 92篇 |
内科学 | 210篇 |
皮肤病学 | 7篇 |
神经病学 | 34篇 |
特种医学 | 147篇 |
外科学 | 58篇 |
综合类 | 33篇 |
预防医学 | 61篇 |
眼科学 | 6篇 |
药学 | 69篇 |
肿瘤学 | 47篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 24篇 |
2017年 | 17篇 |
2016年 | 15篇 |
2015年 | 22篇 |
2014年 | 33篇 |
2013年 | 49篇 |
2012年 | 45篇 |
2011年 | 41篇 |
2010年 | 28篇 |
2009年 | 21篇 |
2008年 | 25篇 |
2007年 | 33篇 |
2006年 | 26篇 |
2005年 | 21篇 |
2004年 | 23篇 |
2003年 | 23篇 |
2002年 | 26篇 |
2001年 | 24篇 |
2000年 | 23篇 |
1999年 | 32篇 |
1998年 | 33篇 |
1997年 | 38篇 |
1996年 | 39篇 |
1995年 | 32篇 |
1994年 | 31篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 22篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 17篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有988条查询结果,搜索用时 13 毫秒
31.
An enzyme-linked immunosorbent assay has been developed for the quantitation of activated Hageman factor-C1 inactivator (HF-C1 INH) complexes. Addition of increasing quantities of either of the major forms of activated Hageman factor (HFa or HFf) to normal plasma or to Hageman factor-deficient plasma leads to a dose-dependent increase in activated HF-C1 INH complexes. As little as 0.5 micrograms/mL of activated HF added to plasma can be detected, corresponding to activation of approximately 2% of plasma HF. The sensitivity of the assay is increased at least tenfold when complexes are formed in HF- deficient plasma, indicating competition between unactivated HF and activated HF-C1 INH complexes for binding to the antibody. Specificity is demonstrated in that addition of activated HF to hereditary angioedema plasma yields less than 1% of the activated HF-C1 INH complex formation obtained with normal plasma. Kaolin activation of HF- deficient plasma yields no detectable complex formation. Kaolin activation of prekallikrein-deficient plasma demonstrates a time- dependent increase in formation of activated HF-C1 INH complex consistent with the ability of HF in this plasma to autoactivate as the time of incubation with the surface is increased. Kaolin treatment of high-molecular weight (HMW) kininogen-deficient plasma yields an even more profound abnormality in the rate of formation of activated HF-C1 INH complexes reflecting the complex role of HMW kininogen in the initiation of contact activation. Although addition of corn inhibitor to plasma prevents activated HF-C1 INH complex formation, it does not inhibit activated HF sufficiently fast to prevent prekallikrein activation. 相似文献
32.
Prevention of degradation of human polymorphonuclear leukocyte proteins by diisopropylfluorophosphate 总被引:27,自引:0,他引:27
Proteases can complicate the characterization of proteins from cells, especially human polymorphonuclear leukocytes (PMN), which contain abundant neutral proteases. We tested the ability of agents to inhibit proteolysis, with special reference to the subunit polypeptides of the contractile proteins actin, myosin, and actin-binding protein (ABP). Phenylmethylsulfonyl fluoride (PMSF), O-phenanthroline, EGTA, EDTA, N- ethylmaleimide, alone or in combinations, failed to prevent extensive proteolysis of the PMN proteins during solubilization of cells with dodecyl sulfate. These inhibitors and also alpha-1-antitrypsin and soybean trypsin inhibitor similarly could not prevent proteolysis during homogenization of cells in cold isosomolar sucrose. Treatment of PMN with greater than or equal to mM diisopropylfluorophosphate (DFP) prior to solubilization or homogenization markedly inhibited proteolysis. PMSF and DFP were equally effective in inhibiting proteolysis in PMN extracts, suggesting that the efficacy of DFP may result from its permeation of intact cells and granules before barriers are disrupted by detergents or homogenization. Treatment of PMN with DFP under conditions inhibiting proteolysis did not affect their rate of phagocytosis. We recommend the use of DFP in future studies correlating functions and protein structure of PMN. 相似文献
33.
In this study we detected a factor that stimulates the proliferation of bone marrow-derived hematopoietic precursors in diffusion chambers implanted in mice. This factor, called diffusible colony-stimulating factor (D-CSF), was found in medium conditioned in the presence of spleen and peripheral blood cells from mice with B cell leukemia (BCL1). After the administration of D-CSF, the number of colonies formed in the plasma clot inside the chamber (CFU-DG) was increased, as were the number of hematopoietic precursors (CFU-MIX, CFU-S, CFU-C, and BFU-E) as judged by a subculture of diffusion chamber contents. Depletion of macrophages and T cells from the spleen cell suspension did not decrease the production of D-CSF, thereby indicating that it was derived from B cells. Neoplastic BCL1 cells appear to be the source because D-CSF could not be detected in medium conditioned with normal B cells. BCL1-conditioned medium (CM) did not enhance CFU-MIX, BFU-E, and CFU-C colony formation in vitro, which suggested that D-CSF is different from multi-CSF, EPA, or CSF. The addition of BCL1 CM to multi- CSF-, erythroid potentiating activity (EPA), and CSF (EL-4CM)- containing cultures had no effect on CFU-MIX, BFU-E, and CFU-C colony formation, thus indicating the absence of a synergistic or inhibitory activity. On the other hand, EL-4 CM, which stimulates CFU-MIX, BFU-E, and CFU-C in vitro, had no effect on CFU-DG in vivo. Biochemical characterization of BCL1 CM revealed that D-CSF is relatively heat stable and loses its bioactivity with protease treatments. It binds to lentil-lectin, according to gel-filtration chromatography has a relative molecular weight of approximately 43,000, and on reverse-phase high-performance liquid chromatography elutes with acetonitrile. These data also indicate that transformed B cells may serve as a source for hematopoietic regulators that act on hematopoietic precursors in vivo. 相似文献
34.
Healthcare professionals’ perceptions of neglect of older people in Mexico: A qualitative secondary analysis
下载免费PDF全文
![点击此处可从《International journal of older people nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
35.
Anthony L Bui Rouselle F Lavado Elizabeth K Johnson Benjamin PC Brooks Michael K Freeman Casey M Graves Annie Haakenstad Benjamin Shoemaker Michael Hanlon Joseph L Dieleman 《Bulletin of the World Health Organization》2015,93(8):566-576D
Objective
To collect, compile and evaluate publicly available national health accounts (NHA) reports produced worldwide between 1996 and 2010.Methods
We downloaded country-generated NHA reports from the World Health Organization global health expenditure database and the Organisation for Economic Co-operation and Development (OECD) StatExtract website. We also obtained reports from Abt Associates, through contacts in individual countries and through an online search. We compiled data in the four main types used in these reports: (i) financing source; (ii) financing agent; (iii) health function; and (iv) health provider. We combined and adjusted data to conform with OECD’s first edition of A system of health accounts manual, (2000).Findings
We identified 872 NHA reports from 117 countries containing a total of 2936 matrices for the four data types. Most countries did not provide complete health expenditure data: only 252 of the 872 reports contained data in all four types. Thirty-eight countries reported an average not-specified-by-kind value greater than 20% for all data types and years. Some countries reported substantial year-on-year changes in both the level and composition of health expenditure that were probably produced by data-generation processes. All study data are publicly available at http://vizhub.healthdata.org/nha/.Conclusion
Data from NHA reports on health expenditure are often incomplete and, in some cases, of questionable quality. Better data would help finance ministries allocate resources to health systems, assist health ministries in allocating capital within the health sector and enable researchers to make accurate comparisons between health systems. 相似文献36.
Norm R.C. Campbell Pedro Ordunez Gloria Giraldo Yenny A. Rodriguez Morales Cintia Lombardi Taskeen Khan Raj Padwal Ross T. Tsuyuki Cherian Varghese 《The Canadian journal of cardiology》2021,37(5):744-755
Globally, cardiovascular diseases (CVDs) are the leading cause of death. Viewed as a threat to the global economy, the United Nations included reducing noncommunicable diseases, including CVDs, in the 2030 sustainable development goals, and the World Health Assembly agreed to a target to reduce noncommunicable diseases 25% by the year 2025. In response, the World Health Organisation led the development of HEARTS, a technical package to guide governments in strengthening primary care to reduce CVDs. HEARTS recommends a public health and health system approach to introduce highly simplified interventions done systematically at a primary health care level and has a focus on hypertension as a clinical entry point. The HEARTS modules include healthy lifestyle counselling, evidence-based treatment protocols, access to essential medicines and technology, CVD risk-based management, team-based care, systems for monitoring, and an implementation guide. There are early positive global experiences in implementing HEARTS. Led by the Pan American Health Organisation, many national governments in the Americas are adopting HEARTS and have shown early success. Unfortunately, in Canada hypertension control is declining in women since 2010-2011 and the dramatic reductions in rates of CVD seen before 2010 have flattened when age adjusted and increased for rates that are not age adjusted, and there are marked increases in absolute numbers of Canadians with adverse CVD outcomes. Several steps that Canada could take to enhance hypertension control are outlined, the core of which is to implement a strong governmental nongovernmental collaborative strategy to prevent and control CVDs, focusing on HEARTS. 相似文献
37.
38.
Ingo Helbig Marielle E M Swinkels Emmelien Aten Almuth Caliebe Ruben van 't Slot Rainer Boor Sarah von Spiczak Hiltrud Muhle Johanna A J?hn Ellen van Binsbergen Onno van Nieuwenhuizen Floor E Jansen Kees P J Braun Gerrit-Jan de Haan Niels Tommerup Ulrich Stephani Helle Hjalgrim Martin Poot Dick Lindhout Eva H Brilstra Rikke S M?ller Bobby PC Koeleman 《European journal of human genetics : EJHG》2014,22(7):896-901
A genetic contribution to a broad range of epilepsies has been postulated, and particularly copy number variations (CNVs) have emerged as significant genetic risk factors. However, the role of CNVs in patients with epilepsies with complex phenotypes is not known. Therefore, we investigated the role of CNVs in patients with unclassified epilepsies and complex phenotypes. A total of 222 patients from three European countries, including patients with structural lesions on magnetic resonance imaging (MRI), dysmorphic features, and multiple congenital anomalies, were clinically evaluated and screened for CNVs. MRI findings including acquired or developmental lesions and patient characteristics were subdivided and analyzed in subgroups. MRI data were available for 88.3% of patients, of whom 41.6% had abnormal MRI findings. Eighty-eight rare CNVs were discovered in 71 out of 222 patients (31.9%). Segregation of all identified variants could be assessed in 42 patients, 11 of which were de novo. The frequency of all structural variants and de novo variants was not statistically different between patients with or without MRI abnormalities or MRI subcategories. Patients with dysmorphic features were more likely to carry a rare CNV. Genome-wide screening methods for rare CNVs may provide clues for the genetic etiology in patients with a broader range of epilepsies than previously anticipated, including in patients with various brain anomalies detectable by MRI. Performing genome-wide screens for rare CNVs can be a valuable contribution to the routine diagnostic workup in patients with a broad range of childhood epilepsies. 相似文献
39.
Juan P. F. García Víctor M. A. Giraldo José J. G. Barrado César D. Casasola 《Journal of Sports Science and Medicine》2013,12(2):316-322
The aims of this study were to measure the effects of a cardiac rehabilitation program based on a modification of a sport (tennis) on quality of life, on various laboratory test parameters and on an exercise stress test, and to determine if the results of this novel activity are equivalent to those of traditional programs (i.e., the use of the bicycle ergometer). The sample consisted of 79 patients with a low-risk acute coronary syndrome. They were divided into three groups: two experimental groups and one control group. One of the experimental groups used the bicycle ergometer as its main physical activity, whereas the other received training in a modified form of tennis lesson. By the end of the 3-month program, triglycerides, cholesterol LDL, cholesterol HDL, (-25 mg·dl-1 and 32.3 mg·dl-1 final, and 15.7 mg·dl-1 and 23.3 mg·dl-1 LDL final, respectively) and exercise capacity improved significantly (by 1.1 metabolic equivalents (METs) and 1.2 METs, respectively), in both experimental groups. We conclude that the application of a comprehensive cardiac rehabilitation program in patients with low-risk acute coronary syndrome based on a program of modified tennis improves exercise tolerance and metabolic parameters, as well as certain physical characteristics that reduce cardiovascular risk.
Key Points
- Cardiac rehabilitation of low risk patients with acute coronary syndrome based on a program of modified tennis produces an improvement in quality of life, lipid profiles and in exercise tolerance
- A cardiac rehabilitation program based on a modification of tennis produces favourable changes in various anthropometric parameters related to the reduction of cardiovascular risk
- The development of programs of cardiac rehabilitation based on modified versions of various sports would advantage the adherence to physical exercise.
40.
Joseph Murray Luciana Anselmi Erika Alejandra Giraldo Gallo Bacy Fleitlich-Bilyk Isabel A. Bordin 《Social psychiatry and psychiatric epidemiology》2013,48(10):1527-1538