全文获取类型
收费全文 | 6331篇 |
免费 | 430篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 217篇 |
妇产科学 | 125篇 |
基础医学 | 833篇 |
口腔科学 | 55篇 |
临床医学 | 988篇 |
内科学 | 1106篇 |
皮肤病学 | 81篇 |
神经病学 | 529篇 |
特种医学 | 139篇 |
外科学 | 703篇 |
综合类 | 49篇 |
一般理论 | 3篇 |
预防医学 | 808篇 |
眼科学 | 65篇 |
药学 | 433篇 |
中国医学 | 3篇 |
肿瘤学 | 578篇 |
出版年
2024年 | 9篇 |
2023年 | 73篇 |
2022年 | 103篇 |
2021年 | 236篇 |
2020年 | 126篇 |
2019年 | 178篇 |
2018年 | 199篇 |
2017年 | 142篇 |
2016年 | 145篇 |
2015年 | 182篇 |
2014年 | 213篇 |
2013年 | 316篇 |
2012年 | 492篇 |
2011年 | 491篇 |
2010年 | 246篇 |
2009年 | 272篇 |
2008年 | 382篇 |
2007年 | 439篇 |
2006年 | 412篇 |
2005年 | 421篇 |
2004年 | 357篇 |
2003年 | 351篇 |
2002年 | 307篇 |
2001年 | 56篇 |
2000年 | 40篇 |
1999年 | 54篇 |
1998年 | 58篇 |
1997年 | 40篇 |
1996年 | 49篇 |
1995年 | 48篇 |
1994年 | 34篇 |
1993年 | 41篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 30篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 17篇 |
1980年 | 8篇 |
1979年 | 13篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1974年 | 5篇 |
排序方式: 共有6780条查询结果,搜索用时 15 毫秒
41.
42.
Luis I. Ruffolo Marsha Pulhamus Theresa Foito Elizabeth Levatino Heather Martin Julie Michels Jan Schriefer Kori Wolcott Derek Wakeman 《Journal of pediatric surgery》2021,56(1):30-36
PurposePediatric gastrostomy tubes (G-tubes) are associated with considerable utilization of healthcare resources. G-tube dislodgement can result in tract disruption and abdominal sepsis. We aimed to reduce early G-tube dislodgement by 25%.MethodsAn interdisciplinary team convened to identify key drivers of G-tube dislodgement and implement initiatives to reduce this complication. A G-tube care bundle was implemented in 2018. Rates of early G-tube dislodgement (within 90 days of insertion) were tracked. 15 months of cases after bundle implementation were compared to 20 months of cases before implementation. Length of stay (LOS, balancing measure) and bundle compliance (process measure) were tracked.ResultsG-tube dislodgements decreased 47% after bundle implementation. Overall, dislodgements after G-tube insertion decreased from 43% to 19% dislodgements per tube inserted, p = 0.004. Reductions were observed for dislodgements occurring in both the inpatient (14% vs. 1.5%) and outpatient (29% vs. 18%) settings. Median LOS was reduced from 15.3 to 7.1 days following implementation, p = 0.004. Process measures demonstrated 75% or greater compliance one year after implementation.ConclusionAn interdisciplinary team using quality improvement science methodology can significantly reduce G-tube dislodgement and improve value after pediatric gastrostomy tube insertion.Type of studyLongitudinal cohort study.Level of evidenceIII. 相似文献
43.
44.
Annals of Surgical Oncology - 相似文献
45.
Olasveengen Theresa M. Semeraro Federico Ristagno Giuseppe Castren Maaret Handley Anthony Kuzovlev Artem Monsieurs Koenraad G. Raffay Violetta Smyth Michael Soar Jasmeet Svavarsdóttir Hildigunnur Perkins Gavin D. 《Notfall & Rettungsmedizin》2021,24(4):386-405
Notfall + Rettungsmedizin - Der Europäische Rat für Wiederbelebung hat diese Leitlinie – Basismaßnahmen zur Wiederbelebung – auf Grundlage des... 相似文献
46.
John W. Bracey Mark A. Tait Sophie B. Hollenberg Theresa O. Wyrick 《Hand (New York, N.Y.)》2021,16(2):253
Background: Telemedicine is an evolving tool to increase patients’ access to subspecialty care. Since 2014, Arkansas has been utilizing telemedicine in the evaluation of patients with hand injuries. The purpose of this study is to assess the effect of this novel telemedicine system for the management of hand trauma on patient transfer. Methods: We reviewed data from the first year of the telemedicine program (2014) and compared it to data from the year prior (2013). Data collection from both years included number of hand consults and need for transfer. From the 2014 data, we also recorded the use of telemedicine, type of transfer, distance of transfer, and time to disposition. Results: During 2013 (pre-telemedicine), there were 263 hand traumas identified. In all, 191 (73%) injuries required transfer to a higher level of care, while 72 (23%) were managed locally. In the first year of the telemedicine program (2014), a total of 331 hand injuries were identified. A total of 298 (90%) resulted in telemedicine consultation with 65% (195) utilizing video encounters. After telemedicine consultation, local management was recommended for 164 injuries (55%) while transfer was recommended for 134 (45%). Using telemedicine, there was a significant decrease in the percentage of transfer for hand injuries (P < .001). Conclusions: The telemedicine program was well utilized and provided patients throughout the state with continuous access to fellowship trained hand surgeons including regions where hand subspecialty care is not available. The program resulted in a significant decrease in the number of hospital transfers for the management of acute hand trauma. 相似文献
47.
Charlotte V. Hobbs Jan Drobeniuc Theresa Kittle John Williams Paul Byers Panayampalli S. Satheshkumar Kengo Inagaki Meagan Stephenson Sara S. Kim Manish M. Patel Brendan Flannery CDC COVID- Response Team CDC COVID- Response Team Bailey Alston Shanna J. Bolcen Darbi Boulay Peter Browning Li Cronin Ebenezer David Tonya Hayden Han Li Travis Lim Panagiotis Maniatis Palak Patel Mathew Pauly Amanda Poe Lili Punkova Vera Semenova Evelene P. Steward-Clark Alexandra Tejada Briana Zellner 《MMWR. Morbidity and mortality weekly report》2021,70(9):312
48.
Nika Adham Laurence A. Borden Lee E. Schechter Eric L. Gustafson Tamara L. Cochran Pierrre J.-J. Vaysse Richard L. Weinshank Theresa A. Branchek 《Naunyn-Schmiedeberg's archives of pharmacology》1993,348(6):566-575
We recently described the cloning of a fifth member of the 5-hydroxytryptamine (5-HT)1 (serotonin1) receptor class that inhibits adenylyl cyclase, namely the human 5-HT1F receptor (Adham et al. 1993 a). In the present study we have examined in greater detail the functional coupling of the 5-HT1F receptor in two different cell lines, NIH-3T3 and LM(tk–) fibroblasts (receptor densities of 1.7 and 4.4 pmol/mg protein, respectively). The maximal inhibitory response elicited by 5-HT was significantly greater in NIH-3T3 as compared to LM(tk–) cells, whereas the EC50 values were comparable.To investigate the relationship between receptor occupancy and inhibition of cAMP accumulation mediated by 5-HT1F receptors in NIH-3T3 cells (and hence the degree of receptor reserve), we used the irreversible receptor antagonist N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ). The half-maximal response required only about 10% receptor occupancy, consistent with a receptor reserve of 90% (88±2.1%, n = 4) for 5-HT-induced inhibition of FSCA. Despite the presence of such a high degree of receptor reserve, a range of intrinsic activities was displayed by structurally diverse classes of compounds. For example, sumatriptan and lysergol were as efficacious as 5-HT itself and thus acted as full agonists, whereas metergoline and 1-NP behaved as partial agonists and as shown previously (Adham et al. 1993a), methiothepin was a silent antagonist (Kb = 438 nM).We have also investigated activation of additional signal transduction pathways by the 5-HT1F receptor and found that the responses differ in the two cell lines with respect to stimulation of phospholipase C. For example, in NIH-3T3 cells no elevation of inositol phosphates (IP) of [Ca2+]i was observed even at very high agonist concentrations (100 M). In contrast, in LM(tk–) cells concentrations of 5-HT as low as 10 nM induced stimulation of IP and a rapid increase of [Ca2+]i. The 5-HT1F receptor failed to alter arachidonic acid release in either cell line.The maximal increase in IP accumulation in LM(tk–) cells was modest, averaging about 100% above basal. The increases of IP and [Ca2+]i required 5-HT concentrations less than one order of magnitude greater than those inhibiting FSCA (EC50 = 17, 55 and 8 nM, respectively), and both responses were blocked by 100 M methiothepin. All three responses (cAMP, IP, and [Ca2+]i) were sensitive to pertussis toxin pre-treatment, suggesting the involvement of Gi/Go protein(s) in these signal transduction pathways. [Ca2+]i was also elevated by sumatriptan, which may provide a mechanism by which this drug causes constriction of the vasculature. In conclusion, these data indicate that the human 5-HT1F receptor can couple to multiple effectors, and that this coupling is cell-type dependent.Abbreviations FSCA
forskolin-stimulated cAMP accumulation
- [Ca2+]
intracellular free calcium concentration
- AA
arachidonic acid
- EEDQ
N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline
- CHO
chinese hamster ovary cell
- LM(tk–)
mouse fibroblast cell
- Bmax
maximal binding site density
- Ki
apparent dissociation constant obtained from competition binding studies
- G protein
guanine nucleotide-binding protein
- HBS
HEPES-buffered saline
- IP
inositol phosphates
- IP3
inositol 1,4,5 trisphosphate
- PLC
phospholipase C
- Kb
antagonist dissociation constant
- Kd
equilibrium dissociation constant
- N-1F-6
stable NIH-3T3 cells expressing the cloned 5-HT1F receptor
- L-1F-3
stable LM(tk–) cells expressing the cloned 5-HT1F receptor
- PTX
pertussis toxin
- BSA
bovine serum albumin
- METH
methiothepin
- SUMA
sumatriptan
- 5-MeO-DMT
5-methoxy-N,N-dimethyltryptamine
- 1-NP
1-(1-napthyl)piperazine
- 5-CT
5-carboxyamidotryptamine
Correspondence to: N. Adham at the above address 相似文献
49.
Lance A. Belchetz M.D. Theresa Berk M.S.S.A. Bharati V. Bapat Ph.D. Zane Cohen M.D. Steven Gallinger M.D. 《Diseases of the colon and rectum》1996,39(4):384-387
Widespread use of prophylactic colectomy has resulted in a reduction in the incidence of colorectal cancer in familial adenomatous polyposis (FAP) patients. A retrospective chart review of families registered at the Steve Atanas Stavro Familial Gastrointestinal Cancer Registry in Toronto was performed to determine whether the decrease in the number of patients developing colorectal cancer implies that causes of mortality in FAP patients are shifting to that of extracolonic manifestations of FAP. Information was available on 140 deaths within 158 families and among 461 individuals with FAP. When stratified by decade, from the 1930s to the 1990s, the ratio of deaths caused by extracolonic manifestations of FAP compared with deaths caused by colorectal cancer was noted to have risen. Even though most deaths in FAP patients are still from colorectal cancer, it appears that screening policies and prophylactic colectomy have resulted in a reduction in the number of FAP patients who develop colorectal cancer. Thus, in recent decades, a greater percentage of deaths in FAP patients appears to be attributable to extracolonic manifestations of the disease. 相似文献
50.
Molecular basis of defective anion transport in L cells expressing recombinant forms of CFTR 总被引:8,自引:0,他引:8
Yang Yiping; Devor Daniel C.; Engelhardt John F.; Ernst Stephen A.; Strong Theresa V.; Collins Francis S.; Cohn Jonathan A.; Frizzell Raymond A.; Wilson James M. 《Human molecular genetics》1993,2(8):1253-1261
Cystic fibrosis (CF) is caused by mutations in the gene encodinga chloride channel called the CF transmembrane conductance regulator(CFTR). A single mutation in this gene, deletion of three nucleotidesthat leads to the absence of phenylalanine 508 (i.e., F508),is found on 70% of all CF chromosomes. To explore the molecularmechanism(s) responsible for defective chloride transport inpatients with CF, we have studied the processing, localization,and function of wild type (W.T.), F508 and G551D CFTR (a GDmissense mutation at position 551) in retrovirus transducedL cells. Cell transduced with W.T. CFTR expressed a 170 kd CFTRprotein that was endoglycosidase H (Endo H) resistant, localizedto the plasma membrane, and generated a cAMP-mediated anionconductance (GCl) when stimulated with standard concentrationsof forskolin (5 µM), cpt cAMP (400 µM) and IBMX(100 µM). The G551D CFTR was indistinguishable from W.T.CFTR with respect to post-translational processing and localization,but it did not produce a cAMP-activated GCI in response to thestandard stimulation cocktail. However, raising the IBMX concentrationto 4 mM produced Gc, in G551D expressing cells. Cells transducedwith F508 CFTR expressed an Endo H sensitive CFTR protein (140kd) that was found in a cytosolic, perinuclear location. Thesecells did not respond to the standard cocktail, but 20% of cellsincreased GCI when the cocktail contained 4 mM IBMX. Incubationof cells at 26°C for 48 hours prior to analysis elicitedresponses in F508 expressing cells at low IBMX concentrations,but had no effect on the responses of cells expressing W.T.or G551D CFTR. The response of F508 to 26°C was associatedwith plasma membrane localization of CFTR protein. These resultssuggest that there are two mechanisms whereby CFTR mutationslead to loss of cAMP-responsive GCI. First, shown by G551D CFTR,the protein can be processed and targeted to the plasma membranecorrectly, but lack full responsiveness to stimulation by cAMP.Second, as examplified by F508 CFTR, a partially functionalprotein which is not targeted to its correct cellular locationcan also lead to loss of the cAMP, responsive GCI. 相似文献