全文获取类型
收费全文 | 15700篇 |
免费 | 1111篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 176篇 |
儿科学 | 530篇 |
妇产科学 | 417篇 |
基础医学 | 2440篇 |
口腔科学 | 239篇 |
临床医学 | 1842篇 |
内科学 | 2693篇 |
皮肤病学 | 406篇 |
神经病学 | 1850篇 |
特种医学 | 432篇 |
外科学 | 1553篇 |
综合类 | 108篇 |
一般理论 | 13篇 |
预防医学 | 1306篇 |
眼科学 | 424篇 |
药学 | 972篇 |
中国医学 | 19篇 |
肿瘤学 | 1430篇 |
出版年
2023年 | 107篇 |
2022年 | 191篇 |
2021年 | 337篇 |
2020年 | 265篇 |
2019年 | 365篇 |
2018年 | 406篇 |
2017年 | 343篇 |
2016年 | 403篇 |
2015年 | 444篇 |
2014年 | 561篇 |
2013年 | 770篇 |
2012年 | 1166篇 |
2011年 | 1107篇 |
2010年 | 670篇 |
2009年 | 590篇 |
2008年 | 941篇 |
2007年 | 980篇 |
2006年 | 957篇 |
2005年 | 907篇 |
2004年 | 851篇 |
2003年 | 796篇 |
2002年 | 739篇 |
2001年 | 146篇 |
2000年 | 114篇 |
1999年 | 196篇 |
1998年 | 193篇 |
1997年 | 151篇 |
1996年 | 134篇 |
1995年 | 133篇 |
1994年 | 83篇 |
1993年 | 97篇 |
1992年 | 99篇 |
1991年 | 104篇 |
1990年 | 87篇 |
1989年 | 88篇 |
1988年 | 92篇 |
1987年 | 81篇 |
1986年 | 82篇 |
1985年 | 87篇 |
1984年 | 66篇 |
1983年 | 65篇 |
1982年 | 61篇 |
1981年 | 35篇 |
1980年 | 47篇 |
1979年 | 55篇 |
1978年 | 35篇 |
1977年 | 41篇 |
1976年 | 49篇 |
1974年 | 39篇 |
1972年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Jenny U. Johansson Nathaniel S. Woodling Qian Wang Maharshi Panchal Xibin Liang Angel Trueba-Saiz Holden D. Brown Siddhita D. Mhatre Taylor Loui Katrin I. Andreasson 《The Journal of clinical investigation》2015,125(1):350-364
Microglia, the innate immune cells of the CNS, perform critical inflammatory and noninflammatory functions that maintain normal neural function. For example, microglia clear misfolded proteins, elaborate trophic factors, and regulate and terminate toxic inflammation. In Alzheimer’s disease (AD), however, beneficial microglial functions become impaired, accelerating synaptic and neuronal loss. Better understanding of the molecular mechanisms that contribute to microglial dysfunction is an important objective for identifying potential strategies to delay progression to AD. The inflammatory cyclooxygenase/prostaglandin E2 (COX/PGE2) pathway has been implicated in preclinical AD development, both in human epidemiology studies and in transgenic rodent models of AD. Here, we evaluated murine models that recapitulate microglial responses to Aβ peptides and determined that microglia-specific deletion of the gene encoding the PGE2 receptor EP2 restores microglial chemotaxis and Aβ clearance, suppresses toxic inflammation, increases cytoprotective insulin-like growth factor 1 (IGF1) signaling, and prevents synaptic injury and memory deficits. Our findings indicate that EP2 signaling suppresses beneficial microglia functions that falter during AD development and suggest that inhibition of the COX/PGE2/EP2 immune pathway has potential as a strategy to restore healthy microglial function and prevent progression to AD. 相似文献
2.
Renaud Snanoudj Nassim Kamar Elisabeth Cassuto Sophie Caillard Marie Metzger Pierre Merville Antoine Thierry Isabelle Jollet Philippe Grimbert Dany Anglicheau Marc Hazzan Gabriel Choukroun Bruno Hurault De Ligny Bénedicte Janbon Vincent Vuiblet Anne Devys Yann Le Meur Michel Delahousse Jean-Luc Taupin 《Kidney international》2019,95(6):1471-1485
3.
Victor Aboyans Louis Labrousse Philippe Lacroix Jér?me Guilloux Seifeddine Sekkal Alexandre Le Guyader Elisabeth Cornu Marc Laskar 《European journal of cardio-thoracic surgery》2006,30(2):300-304
BACKGROUND: Despite major improvement in surgical techniques and intensive care management, stroke remains one of the most devastating complications of coronary artery bypass grafting (CABG). We aimed to determine factors predicting the occurrence of stroke during CABG. A special interest was focused on preoperative therapies. METHODS: We prospectively enrolled 810 consecutive candidates for CABG alone in a specific database, including all pre- and perioperative data (history, clinical, therapeutic, cardiac catheterization, surgical and intensive care data). Univariate tests and then multiple logistic regression analysis were used to determine independent predictive factors. RESULTS: During the first postoperative month, stroke occurred in 11 cases and transient ischemic attack (TIA) in 4 additive cases (cumulative rate: 1.85%). After the multivariate analysis, the following factors remained significant (p<0.05) in the predictive model, with corresponding odds ratios between brackets: redo cardiac surgery (7.45), unstable cardiac status (4.74), past history of cerebrovascular disease (4.14), past history of peripheral arterial disease (3.55), whereas the presence of preoperative statins was protective (0.24, 95% IC: 0.07-0.78). The addition of perioperative data (aortic calcification, postoperative arrhythmia, on/off-pump surgery) did not change the final predictive model. CONCLUSION: To our knowledge, this is the first real-world observational report highlighting the interest of statins for the prevention of stroke in the very special situation of CABG. Even though according to randomized trials coronary patients have a benefit from these drugs, a special level of interest should be directed towards those presenting the above-mentioned risk factors. 相似文献
4.
Rajnish Mago MD John-Paul Gomez MD Namita Gupta MBBS Elisabeth J. S. Kunkel MD 《Current psychiatry reports》2006,8(3):228-233
Anxiety disorders and anxiety symptoms are highly prevalent in the general population and more so in the medically ill. They
have a number of negative consequences for these patients and may worsen the outcome of the medical illness and increase health
care utilization. In the evaluation of these patients, it is of paramount importance to identify the etiology of the anxiety
and, in particular, to differentiate primary from secondary anxiety. Management includes medications (especially benzodiazepines
and selective serotonin reuptake inhibitors) and psychotherapy (particularly cognitive-behavioral therapy). 相似文献
5.
Peter Chiba Barbara Tell Walter Jger Elisabeth Richter Manuela Hitzlera Gerhard Ecker 《Archiv der Pharmazie》1997,330(11):343-347
A series of 5-hydroxy and 5-benzyloxy analogs of the antiarrhythmic and multidrug resistance (MDR) modulating drug propafenone was synthesized and the MDR-modulating activity of the compounds was evaluated using a daunomycin efflux assay system. The key step of the synthesis is the selective reduction of the double bond in 1 without cleavage of the benzyl group thus leading to the phenol 3 . Alkylation with epichlorohydrine followed by nucleophilic epoxide ring opening gave the benzylated target compounds 5a–d . Subsequent cleavage of the benzyl group gave the 5-hydroxy analogs 6a–d . Structure activity relationship studies showed, that the 5-hydroxy derivates 6a–d fit the log P/log potency correlation line previously established for a series of propafenone analogs. In contrast, all four 5-benzyloxy analogs 5a–d showed almost identical EC50 values, independent of their log P value. 相似文献
6.
Drug-resistance in Streptococcus pneumoniae isolates among Spanish middle aged and older adults with community-acquired pneumonia 总被引:1,自引:0,他引:1
Angel Vila-Corcoles Ferran Bejarano-Romero Elisabeth Salsench Olga Ochoa-Gondar Cinta de Diego Frederic Gomez-Bertomeu Xavier Raga-Luria Xavier Cliville-Guasch Victoria Arija 《BMC infectious diseases》2009,9(1):36
Background
Pneumococcal diseases remain a major cause of morbidity and mortality worldwide. Updated data on drug-resistance from different populations may be important to recognize changes in disease patterns. This study assessed current levels of penicilin resistance among Streptococcus Pneumoniae causing pneumonia in Spanish middle age and older adults. 相似文献7.
Age determines memory for face identity and expression 总被引:1,自引:1,他引:0
Egemen SAVASKAN Sandra Elisabeth MÜLLER reas BÖHRINGER Christine PHILIPPSEN Franz MÜLLER-SPAHN Hartmut SCHÄCHINGER 《Psychogeriatrics》2007,7(2):49-57
Background: The recognition of facial expressions is an important component of emotion processing which contributes to interactional behavior. One of the factors highly associated with potential decline of ability in behavioral tasks is age. Methods: We have investigated age‐related changes in facial identity and expression memory of healthy subjects in three age groups: young adults (20–40 years), elderly adults (60–80 years) and, for the first time in the literature, very old adults (over 80 years of age). Using a picture test, photographs of faces with happy or angry expressions were presented to study participants during the encoding task, and the memory for identity and emotional facial expression was investigated in a subsequent recognition task showing emotionally neutral faces. Half of the faces presented in the recognition task were initially shown in the encoding task. Results: Age interacted with the memory process: the ability to recognize both facial identity and emotional expression declined with advanced age. Happy facial expressions were better recognized in all age groups. Although there was a continuous overall decrease in recognition of both happy and angry expressions with advanced age, the effect favoring happy facial expressions was stable also in very old adults. Other factors such as gender or educational level did not affect the memory process for facial expressions. Conclusions: Our findings suggest that age is a significant determinant of memory for facial identity and emotional expression, and that, similar to younger adults, the recognition process of the elderly favors happy emotional facial expressions. 相似文献
8.
9.
Changes to the ocular biota with time in extended- and daily-wear disposable contact lens use. 总被引:3,自引:0,他引:3 下载免费PDF全文
F Stapleton M D Willcox C M Fleming S Hickson D F Sweeney B A Holden 《Infection and immunity》1995,63(11):4501-4505
Gram-negative bacteria may play a role in the etiology of certain soft contact lens (SCL)-related diseases. Contact lens (CL) wear may modify the normal ocular biota, providing a more favorable environment for potential pathogens. This study reports temporal changes in ocular biota in daily-wear (DW) and extended-wear (EW) disposable SCL use in experienced and neophyte wearers. Lid margin and bulbar conjunctival biota were sampled prior to CL fitting in 26 previous DW SCL users, 18 previous EW SCL users, and 26 neophytes. Wearers were fitted with an etafilcon A CL in one eye and a polymacon CL in the fellow eye. Lenses were worn on a daily basis by the 26 previous DW SCL wearers and on an EW basis by the remaining 44 subjects. The ocular biota was further sampled after 1, 3, 6, 9, and 12 months of wear. The ocular biota consisted of coagulase-negative staphylococci, Corynebacterium spp., Micrococcus spp., and Propionibacterium spp. Potential pathogens were rarely isolated at baseline. No significant trend of increasing ocular colonization was shown for extended CL wear. Lid and conjunctival colonization increased with DW SCL use (P < 0.001), although this increase occurred for nonpathogenic species only. Fewer potential pathogens were isolated from DW SCL than from EW SCL users (P < 0.05). The lid margin consistently showed greater colonization than the conjunctiva and may be a source of potential pathogens during CL wear. Hydrogel CL wear appears to modify the ocular biota. An increased number of commensal organisms were present in DW SCL use. EW SCL use altered the spectrum of organisms isolated. These alterations may suppress the normal ocular defense mechanisms and may be relevant in the pathogenesis of CL-related disease. 相似文献
10.
Michael Hutchinson Jonathon O'Riordan Mohammed Javed Etain Quin Donal Macerlaine Teresa Willcox Nollaig Parfrey Tamas G. Nagy Elisabeth Tournier-Lasserve 《Annals of neurology》1995,38(5):817-824
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a recently described familial cerebrovascular disorder shown to map to chromosome 19q12. Familial hemiplegic migraine has also been shown in some families to map close to the CADASIL locus. The fully developed CADASIL phenotype consists of recurrent strokes developing in the fourth decade, progressing to a pseudobulbar palsy, spastic quadriparesis, and subcortical dementia. In an Irish family 15 members were fully investigated by magnetic resonance scanning; 10 had typical magnetic resonance features of CADASIL. Five members of this family had familial hemiplegic migraine and 4 of these had magnetic resonance evidence of CADASIL. Two other members had migraine with and without aura as a presenting clinical symptom of CADASIL. This disorder has been shown by linkage analysis to map to the CADASIL locus at chromosome 19. The phenotype at presentation of CADASIL in this family was variable and age related and included familial hemiplegic migraine, migraine with and without aura, transient ischemic attacks, strokes, and spinal cord infarction. This family study increases our understanding of the spectrum of clinical manifestations of this underrecognized familial cerebrovascular disorder. 相似文献