全文获取类型
收费全文 | 2037篇 |
免费 | 186篇 |
国内免费 | 3篇 |
出版年
2021年 | 29篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 30篇 |
2016年 | 46篇 |
2015年 | 74篇 |
2014年 | 79篇 |
2013年 | 92篇 |
2012年 | 112篇 |
2011年 | 118篇 |
2010年 | 50篇 |
2009年 | 44篇 |
2008年 | 64篇 |
2007年 | 69篇 |
2006年 | 85篇 |
2005年 | 63篇 |
2004年 | 69篇 |
2003年 | 68篇 |
2002年 | 54篇 |
2001年 | 49篇 |
2000年 | 42篇 |
1999年 | 42篇 |
1998年 | 22篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1992年 | 40篇 |
1991年 | 37篇 |
1990年 | 39篇 |
1989年 | 38篇 |
1988年 | 42篇 |
1987年 | 32篇 |
1986年 | 23篇 |
1985年 | 27篇 |
1984年 | 39篇 |
1983年 | 31篇 |
1982年 | 23篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 26篇 |
1976年 | 21篇 |
1974年 | 25篇 |
1973年 | 21篇 |
1972年 | 30篇 |
1970年 | 18篇 |
1969年 | 15篇 |
排序方式: 共有2226条查询结果,搜索用时 31 毫秒
101.
Laparoscopic appendectomy to remove a metallic foreign body in a wild Bornean orangutan (Pongo pygmaeus) undergoing rehabilitation
下载免费PDF全文
![点击此处可从《Journal of medical primatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Karmele Llano Sanchez Ayu B. Handayani Christine L. Nelson Jaclyn W.L. Eng Wendi Prameswari Nigel Hicks Romain Pizzi 《Journal of medical primatology》2016,45(6):327-329
A laparoscopic appendectomy was performed in a wild orangutan (Pongo pygmaeus) undergoing rehabilitation, for a metal nail found on radiographs, using 3‐mm instrumentation. Post‐operative healing was rapid and uneventful, with return to the forest within 10 days. This is the first report of minimally invasive surgery in a wild orangutan. 相似文献
102.
Grace C. Lee Ronald G. Hall Natalie K. Boyd Steven D. Dallas Liem C. Du Lucina B. Treviño Sylvia B. Treviño Chad Retzloff Kenneth A. Lawson James Wilson Randall J. Olsen Yufeng Wang Christopher R. Frei 《Annals of clinical microbiology and antimicrobials》2016,15(1):58
Background
The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs.Methods
This was a prospective, observational study among 14 primary care clinics within the South Texas Ambulatory Research Network. The primary outcome was treatment failure within 90 days of the initial visit. Univariate associations between the explanatory variables and treatment failure were examined. A generalized linear mixed-effect model was developed to identify independent risk factors associated with treatment failure.Results
Overall, 21% (22/106) patients with S. aureus SSTIs experienced treatment failure. The occurrence of treatment failure was similar among patients with methicillin-resistant S. aureus and those with methicillin-susceptible S. aureus SSTIs (19 vs. 24%; p = 0.70). Independent predictors of treatment failure among cases with S. aureus SSTIs was a duration of infection of ≥7 days prior to initial visit [aOR, 6.02 (95% CI 1.74–19.61)] and a lesion diameter size ≥5 cm [5.25 (1.58–17.20)].Conclusions
Predictors for treatment failure included a duration of infection for ≥7 days prior to the initial visit and a wound diameter of ≥5 cm. A heightened awareness of these risk factors could help direct targeted interventions in high-risk populations.103.
104.
Ning Jia Charlie Y. Mo Chongyuan Wang Edward T. Eng Luciano A. Marraffini Dinshaw J. Patel 《Molecular cell》2019,73(2):264-277.e5
105.
Martyn Eliott Simon Lawson Andrew Hayes Valerie Debuse Alan York Tom Lewis 《Austral ecology》2019,44(4):609-620
Fire has a varied influence on plant and animal species through direct (e.g. fire‐induced mortality) and indirect (e.g. modification of habitat) effects. Our understanding of the influence of fire regime on invertebrates and their response to fire‐induced modifications to habitat is poor. We aimed to determine the response of a beetle family (Coleoptera: Cerambycidae) to varying fire treatments and hypothesised that the abundance of cerambycid beetles is influenced by fire frequency due to modifications in habitat associated with the fire treatments. Arthropods were sampled across 3 months in annually and triennially burnt areas (treatments starting in 1952 and 1973 respectively), an area unburnt since 1946, and a former unburnt treatment, burnt by wildfire in 2006. Eleven different cerambycid taxa were collected using flight intercept panel traps, dominated by three species (Ipomoria tillides, Adrium sp. and Bethelium signiferum) which made up 99% of individuals collected. Over the sampling period the long unburnt treatment had significantly lower species richness than the triennial and wildfire treatments. Cerambycid abundance was significantly higher in the triennially burnt treatment than in all other fire treatments. Ipomoria tillides was more abundant in both frequently burnt treatments, Adrium sp. was more common in triennially burnt areas, whereas B. signiferum, was more common in the wildfire affected treatment. Some, but not all, cerambycid beetles were more common in areas with a more open understorey (i.e. resulting from frequent burning), and lower tree basal area, as this likely influences their ability to fly easily between food sources. Cerambycid abundance was positively related to the volume of coarse woody debris and healthy tree crowns. Cerambycid beetles were clearly influenced by historic fire regime, suggesting that changes in fire regime can potentially have a profound influence on arthropod assemblages, and subsequent influences on ecosystem processes, which are currently poorly understood. 相似文献
106.
107.
We have identified in Caenorhabditis elegans a homologue of the vertebrate Crim1, crm-1, which encodes a putative transmembrane protein with multiple cysteine-rich (CR) domains known to have bone morphogenetic proteins (BMPs) binding activity. Using the body morphology of C. elegans as an indicator, we showed that attenuation of crm-1 activity leads to a small body phenotype reminiscent of that of BMP pathway mutants. We showed that the crm-1 loss-of-function phenotype can be rescued by constitutive supply of sma-4 activity. crm-1 can enhance BMP signaling and this activity is dependent on the presence of the DBL-1 ligand and its receptors. crm-1 is expressed in neurons at the ventral nerve cord, where the DBL-1 ligand is produced. However, ectopic expression experiments reveal that crm-1 gene products act outside the DBL-1 producing cells and function non-autonomously to facilitate dbl/sma pathway signaling to control body size. 相似文献
108.
Chou WL Chuang LM Chou CC Wang AH Lawson JA FitzGerald GA Chang ZF 《The Journal of biological chemistry》2007,282(25):18162-18172
109.
110.
Li F Pincet F Perez E Eng WS Melia TJ Rothman JE Tareste D 《Nature structural & molecular biology》2007,14(10):890-896
Membrane fusion occurs when SNAREpins fold up between lipid bilayers. How much energy is generated during SNAREpin folding and how this energy is coupled to the fusion of apposing membranes is unknown. We have used a surface forces apparatus to determine the energetics and dynamics of SNAREpin formation and characterize the different intermediate structures sampled by cognate SNAREs in the course of their assembly. The interaction energy-versus-distance profiles of assembling SNAREpins reveal that SNARE motifs begin to interact when the membranes are 8 nm apart. Even after very close approach of the bilayers (approximately 2-4 nm), the SNAREpins remain partly unstructured in their membrane-proximal region. The energy stabilizing a single SNAREpin in this configuration (35 k(B)T) corresponds closely with the energy needed to fuse outer but not inner leaflets (hemifusion) of pure lipid bilayers (40-50 k(B)T). 相似文献