全文获取类型
收费全文 | 2658篇 |
免费 | 175篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 132篇 |
妇产科学 | 36篇 |
基础医学 | 288篇 |
口腔科学 | 60篇 |
临床医学 | 284篇 |
内科学 | 599篇 |
皮肤病学 | 49篇 |
神经病学 | 205篇 |
特种医学 | 44篇 |
外国民族医学 | 1篇 |
外科学 | 488篇 |
综合类 | 43篇 |
预防医学 | 180篇 |
眼科学 | 19篇 |
药学 | 214篇 |
中国医学 | 13篇 |
肿瘤学 | 153篇 |
出版年
2023年 | 29篇 |
2022年 | 54篇 |
2021年 | 104篇 |
2020年 | 54篇 |
2019年 | 90篇 |
2018年 | 107篇 |
2017年 | 72篇 |
2016年 | 64篇 |
2015年 | 85篇 |
2014年 | 105篇 |
2013年 | 116篇 |
2012年 | 199篇 |
2011年 | 181篇 |
2010年 | 117篇 |
2009年 | 88篇 |
2008年 | 151篇 |
2007年 | 119篇 |
2006年 | 96篇 |
2005年 | 118篇 |
2004年 | 137篇 |
2003年 | 94篇 |
2002年 | 104篇 |
2001年 | 48篇 |
2000年 | 68篇 |
1999年 | 67篇 |
1998年 | 17篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1992年 | 24篇 |
1991年 | 23篇 |
1990年 | 25篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 30篇 |
1986年 | 23篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1974年 | 11篇 |
1973年 | 9篇 |
1972年 | 8篇 |
1971年 | 6篇 |
1970年 | 6篇 |
排序方式: 共有2839条查询结果,搜索用时 15 毫秒
71.
Mushtaq Mir Sladjana Prisic Choong-Min Kang Shichun Lun Haidan Guo Jeffrey P. Murry Eric J. Rubin Robert N. Husson 《Infection and immunity》2014,82(10):4104-4117
To persist and cause disease in the host, Mycobacterium tuberculosis must adapt to its environment during infection. Adaptations include changes in nutrient utilization and alterations in growth rate. M. tuberculosis Rv1422 is a conserved gene of unknown function that was found in a genetic screen to interact with the mce4 cholesterol uptake locus. The Rv1422 protein is phosphorylated by the M. tuberculosis Ser/Thr kinases PknA and PknB, which regulate cell growth and cell wall synthesis. Bacillus subtilis strains lacking the Rv1422 homologue yvcK grow poorly on several carbon sources, and yvcK is required for proper localization of peptidoglycan synthesis. Here we show that Mycobacterium smegmatis and M. tuberculosis strains lacking Rv1422 have growth defects in minimal medium containing limiting amounts of several different carbon sources. These strains also have morphological abnormalities, including shortened and bulging cells, suggesting a cell wall defect. In both mycobacterial species, the Rv1422 protein localizes uniquely to the growing cell pole, the site of peptidoglycan synthesis in mycobacteria. An M. tuberculosis ΔRv1422 strain is markedly attenuated for virulence in a mouse infection model, where it elicits decreased inflammation in the lungs and shows impaired bacterial persistence. These findings led us to name this gene cuvA (carbon utilization and virulence protein A) and to suggest a model in which deletion of cuvA leads to changes in nutrient uptake and/or metabolism that affect cell wall structure, morphology, and virulence. Its role in virulence suggests that CuvA may be a useful target for novel inhibitors of M. tuberculosis during infection. 相似文献
72.
David Cáceres-Castillo Yussel Pérez-Navarro Julio César Torres-Romero Gumersindo Mirón-López Jimmy Ceballos-Cruz Victor Arana-Argáez Laura Vázquez-Carrillo José Manuel Fernández-Sánchez María Elizbeth Alvarez-Sánchez 《Drug development research》2019,80(1):155-161
Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is the most common nonviral sexually transmitted infection worldwide. Although drug treatment is available, unpleasant side effects and increased resistance to the nitroimidazole family have been documented. Hence, there is a need for the identification of new and safe therapeutic agents against T. vaginalis. Antimicrobial activity of anthraquinone compounds has been reported by a number of authors. The genus Morinda is well known for the diversity of anthraquinones with numerous biological activities. A new anthraquinone, lucidin-ω-isopropyl ether, was isolated from the roots of Morinda panamensis Seem. The structure of the compound was determined by 1H and 13C Nuclear Magnetic Resonance (NMR) analyses, in addition to comparison with literature reports. Using in vitro susceptibility assay, the half inhibitory concentration (IC50) of lucidin-ω-isopropyl ether for T. vaginalis (1.32 μg/mL) was found similar to that of metronidazole concentration tested (6 μM = 1.03 μg/mL). In addition, this anthraquinone was capable of inhibiting the parasite's ability to kill HeLa cells and decreased proteolytic activity of the proteinase TvMP50 from T. vaginalis. This was associated with the decreased expression of the mp50 gene. These results demonstrate the trichomonicidal potential by lucidin-ω-isopropyl ether. Further action-mode studies are necessary to elucidate the antiparasitic mechanism of this new anthraquinone to develop a more potent antitrichomonal agent. 相似文献
73.
74.
75.
76.
77.
78.
Rüffer A Klopsch C Münch F Gottschalk U Mir TS Weil J Reichenspurner HC Cesnjevar RA 《The Thoracic and cardiovascular surgeon》2012,60(3):189-194
Objective aortic arch repair (AAR) on the beating heart may reduce cross-clamping times and offer improved postoperative cardiac function.Methods A single-center review of all patients (n = 24) who underwent surgical AAR during biventricular repair between 01/2006 and 01/2008 was done. All patients were operated on under cardiopulmonary bypass (CPB) with antegrade cerebral perfusion (ACP). During AAR, 13 patients (group 1) received cardioplegic arrest, and were compared to 11 patients (group 2) who underwent a beating-heart modification with selective myocardial perfusion. Seventeen patients had additional intracardiac lesions and underwent simultaneous correction during the procedure.Results Durations of CPB, AAR and ACP did not differ statistically between groups. Cardioplegic arrest time was significantly lower in group 1 (34 ± 13 vs. 76 ± 11 min, p = 0.02) and resulted in a subsequent reduction of myocardial ischemic damage as borne out by lower postoperative levels of troponin T and CK-MB (2.5 ± 0.7 vs. 7.1 ± 1.4 ng/mL, p = 0.02; 68.7 ± 11.5 vs. 149.1 ± 27.2 U/l, p = 0.03). We observed an enhanced patient recovery with shorter inotropic and ventilatory support times (p < 0.05).Conclusion Pediatric aortic arch correction on a CPB beating heart with selective myocardial perfusion is technically feasible and safe. The reduction of the myocardial ischemic time is effective and results in less myocardial damage. 相似文献
79.
M. F. Lorenzo-Gómez B. Padilla-Fernández F. J. García-Criado J. A. Mirón-Canelo A. Gil-Vicente A. Nieto-Huertos J. M. Silva-Abuin 《International urogynecology journal》2013,24(1):127-134
Introduction and hypothesis
Urinary tract infections (UTIs) are considered the most common bacterial infections, especially in women. The objective of this study was to evaluate the use of the sublingual bacterial vaccine Uromune® in order to prevent recurrent UTIs (RUTIs).Methods
This study was conceived as a multicenter observational study. The clinical history of 319 women who presented at least 2 episodes of UTI in the last 6 months or 3 in 12 months was reviewed. Data related to treatment and clinical evolution were recorded and analyzed. A total of 159 patients received prophylactic treatment with Uromune® for a period of 3 months (group A) and 160 with sulfamethoxazole/trimethoprim 200/40 mg/day for a period of 6 months (group B). Uromune® contained an inactivated bacterial cell suspension of selected strains of Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, and Enterococcus faecalis.Results
Patients in group A experienced a highly significant reduction in the number of infections compared to patients in group B. In the first 3 months, the mean number of infections was 0.36 versus 1.60 (P?<?0.0001), respectively. A significant reduction was also observed after 9 and 15 months (P?<?0.0001). The numbers of patients who did not have any UTI at 3, 9, and 15 months were 101, 90, and 55 in group A versus 9, 4, and 0 in group B (P?<?0.0001).Conclusions
The results obtained in this study favor the use of this bacterial-based therapeutic vaccine as an effective strategy to reduce frequency, duration, severity, and costs of RUTIs. 相似文献80.
Alfons Schnitzler Pablo Mir Matthew A. Brodsky Leonard Verhagen Sergiu Groppa Ramiro Alvarez Andrew Evans Marta Blazquez Sean Nagel Julie G. Pilitsis Monika Pötter-Nerger Winona Tse Leonardo Almeida Nestor Tomycz Joohi Jimenez-Shahed Witold Libionka Fatima Carrillo Christian J. Hartmann Matthew A. Brodsky 《Neuromodulation》2022,25(6):817-828
ObjectivePublished reports on directional deep brain stimulation (DBS) have been limited to small, single-center investigations. Therapeutic window (TW) is used to describe the range of stimulation amplitudes achieving symptom relief without side effects. This crossover study performed a randomized double-blind assessment of TW for directional and omnidirectional DBS in a large cohort of patients implanted with a DBS system in the subthalamic nucleus for Parkinson's disease.Materials and MethodsParticipants received omnidirectional stimulation for the first three months after initial study programming, followed by directional DBS for the following three months. The primary endpoint was a double-blind, randomized evaluation of TW for directional vs omnidirectional stimulation at three months after initial study programming. Additional data recorded at three- and six-month follow-ups included stimulation preference, therapeutic current strength, Unified Parkinson's Disease Rating Scale (UPDRS) part III motor score, and quality of life.ResultsThe study enrolled 234 subjects (62 ± 8 years, 33% female). TW was wider using directional stimulation in 183 of 202 subjects (90.6%). The mean increase in TW with directional stimulation was 41% (2.98 ± 1.38 mA, compared to 2.11 ± 1.33 mA for omnidirectional). UPDRS part III motor score on medication improved 42.4% at three months (after three months of omnidirectional stimulation) and 43.3% at six months (after three months of directional stimulation) with stimulation on, compared to stimulation off. After six months, 52.8% of subjects blinded to stimulation type (102/193) preferred the period with directional stimulation, and 25.9% (50/193) preferred the omnidirectional period. The directional period was preferred by 58.5% of clinicians (113/193) vs 21.2% (41/193) who preferred the omnidirectional period.ConclusionDirectional stimulation yielded a wider TW compared to omnidirectional stimulation and was preferred by blinded subjects and clinicians. 相似文献