全文获取类型
收费全文 | 3694篇 |
免费 | 279篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 56篇 |
妇产科学 | 17篇 |
基础医学 | 644篇 |
口腔科学 | 67篇 |
临床医学 | 246篇 |
内科学 | 991篇 |
皮肤病学 | 56篇 |
神经病学 | 351篇 |
特种医学 | 70篇 |
外科学 | 577篇 |
综合类 | 44篇 |
预防医学 | 68篇 |
眼科学 | 121篇 |
药学 | 228篇 |
中国医学 | 6篇 |
肿瘤学 | 430篇 |
出版年
2023年 | 22篇 |
2022年 | 40篇 |
2021年 | 98篇 |
2020年 | 42篇 |
2019年 | 45篇 |
2018年 | 61篇 |
2017年 | 51篇 |
2016年 | 80篇 |
2015年 | 93篇 |
2014年 | 102篇 |
2013年 | 128篇 |
2012年 | 199篇 |
2011年 | 229篇 |
2010年 | 106篇 |
2009年 | 96篇 |
2008年 | 160篇 |
2007年 | 196篇 |
2006年 | 235篇 |
2005年 | 196篇 |
2004年 | 196篇 |
2003年 | 190篇 |
2002年 | 166篇 |
2001年 | 91篇 |
2000年 | 68篇 |
1999年 | 80篇 |
1998年 | 45篇 |
1997年 | 43篇 |
1996年 | 34篇 |
1995年 | 38篇 |
1994年 | 42篇 |
1993年 | 25篇 |
1992年 | 67篇 |
1991年 | 63篇 |
1990年 | 74篇 |
1989年 | 62篇 |
1988年 | 68篇 |
1987年 | 73篇 |
1986年 | 65篇 |
1985年 | 55篇 |
1984年 | 49篇 |
1983年 | 46篇 |
1982年 | 23篇 |
1981年 | 20篇 |
1980年 | 20篇 |
1979年 | 29篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1973年 | 8篇 |
1969年 | 10篇 |
1966年 | 7篇 |
排序方式: 共有4011条查询结果,搜索用时 15 毫秒
1.
2.
3.
Yasuyuki Suzuki Kazuyuki Daitoku Masahito Minakawa Kozo Fukui Ikuo Fukuda 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2006,54(1):44-46
We report the case of a 4-year-old girl who had quadricuspid aortic valve regurgitation with tetralogy of Fallot and pulmonary
atresia. This combination is very uncommon. Aortic valve replacement was performed successfully due to aortic regurgitation
which had progressed one year after the total repair. The dilated aortic annulus plus quadricuspid aortic valve may result
in progressive aortic regurgitation for a short period. 相似文献
4.
Nagai Masahiro Nishikawa Noriko Yabe Hayato Moritoyo Hiroyoko Moritoyo Takashi Shigematsu Yuji Nomoto Masahiro 《Journal of neurology》2007,254(4):IV54-IV57
Journal of Neurology - A high incidence of valvular heart disease in Parkinson's disease (PD) patients treated with ergot-derived dopamine agonists, such as cabergoline and pergolide, has been... 相似文献
5.
OBJECTIVE: The aim of this study was to evaluate the relationship between the degree of conversion (DC) of composites and the light intensity using LED-curing units and also to determine the amount of exposure required to achieve optimal curing. METHOD: The light outputs of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in modified ISO standards, ISO/TS10650 and ISO 4049, respectively. The distributions of DC in composites were investigated by IR spectra of microareas obtained at various depths from the irradiated surface of thin specimens cut out from the cured composites. IR spectra were measured using a Fourier transform infrared spectrometer equipped with a microscopic unit. DC was calculated from the changes in the amount of C=C double bonds in the IR spectra. RESULTS: The light intensity at various depths through the cured composite was calculated from the attenuation coefficient of each material, obtained from the linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. There was a third or fourth order regression relationship between DC and the logarithm of total light energy at a particular depth. SIGNIFICANCE: The minimum light energy required to produce a saturated DC was about 1000 s mW/cm2. 相似文献
6.
Transient depletion of nucleus accumbens dopamine content may contribute to initial akinesia induced by MPTP in common marmosets 总被引:2,自引:0,他引:2
Acute treatment of common marmosets with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) caused an initial profound akinesia and other motor deficits. However, over the following months akinesia gradually disappeared although the animals remained clumsy and poorly coordinated. At 10 days following MPTP treatment there was a profound decrease in the dopamine, HVA and DOPAC content of the caudate nucleus, putamen and nucleus accumbens. By 3-4 months following MPTP treatment the animals had largely recovered from their akinesia, but the caudate nucleus and putamen dopamine, HVA and DOPAC content remained low. In contrast, the dopamine content of the nucleus accumbens had returned towards normal and the metabolite levels were higher than at 10 days. No overall alterations in 5HT or 5HIAA levels were observed at either time point. The transient and reversible nature of dopamine loss in the nucleus accumbens may contribute to the initial profound akinesia exhibited by common marmosets treated with MPTP. The restoration of dopamine levels in the nucleus accumbens may be partially responsible for the subsequent recovery of motor function that occurs in MPTP-treated marmosets. 相似文献
7.
While an exacerbation in allergic symptoms corresponding to seasons has long been reported, few studies have investigated the association between the season of birth and allergic disorders. The aim of this study was to investigate whether the climatologic data before and after birth affected the incidence of atopic dermatitis (AD) and the results of allergy-related blood tests in early infancy. From February 1995 to January 2000, 2136 infants were tested for AD and followed for 12 months. AD patients were tested by using allergy-related blood tests. Data were compared according to the month of birth and the climatologic data using a computed statistical software package. Six hundred and thirty infants had AD before 12 months old, and significant differences were found according to the season of birth (p < 0.0001). Infants born in spring showed the lowest (22.3%) incidence, while those born in autumn showed the highest (34.6%). In 369 patients, total serum IgE levels, and serum specific IgE levels with egg white at 3 months old were also different according to the season of birth. All of these levels were lower in patients born in spring and summer, and higher in patients born in autumn and winter. Furthermore, the cumulative sunshine amount during the 3 months before and after birth was inversely correlated, while the average temperature over the 3 months before birth was positively correlated to the incidence of AD according to the month of birth. The climatologic data around birth may play an important role in whether an infant develops allergies. 相似文献
8.
Satsuki Sumitani Shu-Ichi Ueno Yasuhito Ishimoto Takahide Taniguchi Masahito Tomotake Ikuyo Motoki Ken Yamauchi Tetsuro Ohmori 《Seishin shinkeigaku zasshi》2006,108(12):1282-1292
BACKGROUND: Although selective serotonin reuptake inhibitors (SSRIs) are the mainstay of pharmacological treatment for obsessive-compulsive disorder (OCD), some OCD patients do not show improvement. Sometimes, the addition of a low-dose atypical antipsychotic, such as risperidone, or olanzapine, to ongoing SSRI treatment has been shown to be effective. However, there are patients who still show no response after trials with this augmentation therapy. In the present study, we examined the clinical features of OCD patients who showed different responses to pharmacological treatment. SUBJECTS AND METHOD: Fifty OCD patients were divided into three groups according to their pharmacological responses: responders to SSRI (group A: n= 25), responders to SSRI with an atypical antipsychotic (group B: n= 15), and non-responders to both SSRI and SSRI with an atypical antipsychotic (group C: n= 10). We examined the clinical features such as age, sex, age of onset, duration of illness, types of obsessive-compulsive symptoms, severity, improvement after treatment, insight into disease, depression, comorbidity, involving family members in compulsive or ritualistic behavior, and the level of social adaptation of each OCD group. RESULTS: Twenty five patients showed a good response to SSRI monotherapy, 15 showed a response to antipsychotic augmentation, and 10 were non-responders to both SSRI and SSRI with an atypical antipsychotic. Significantly lower insight levels were observed only in group B and higher depressive levels in group C. OCD patients who were refractory to SSRI monotherapy showed comorbidity at a significantly higher frequency. OCD patients in group A showed significantly greater improvement, and group B showed inferior social adaptation after treatment. There were no significant differences in age, sex, age of onset, duration of illness, severity, involving family members in compulsive or ritualistic behavior, and social adaptation before treatment in the three OCD groups. CONCLUSION: There were differences in the clinical features of OCD patients who showed different responses to pharmacological treatment. Our results suggest that OCD is clinically and biologically heterogeneous. It may be important to divide OCD patients into subgroups for future studies. 相似文献
9.
Masahito Minakawa Kenji Takahashi Norihiro Kondo Masaharu Hatakeyama Toshihiko Kuga Ikuo Fukuda 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2003,51(11):582-587
Objective: Reoperative coronary bypass grafting is at high risk. Particularly in redo cases where the patent graft is running near
the midline of the sternum, the graft may be exposed to injury by a median sternotomy and subsequent dissection. Whereas,
off-pump bypass grafting from the left axillary artery or descending thoracic artery by a left thoracotomy approach is safe
for preventing graft damage.Methods: From March 1998 to February 2002, we performed off-pump coronary artery bypass grafting by a left thoracotomy approach in
9 patients. The left axillary artery was used as the inflow vessel in 4 cases, and the descending thoracic, aorta in 5.Results: The radial artery was anastomosed proximally to the axillary artery in 4 cases and the descending thoracic aorta in one
case. The saphenous vein graft was anastomosed, proximally to the descending thoracic aorta in 4 cases. Transdiaphragmatic
minimally invasive bypass grafting for the right coronary artery was simultaneously performed in 3 cases. Postoperative cardiac
events were ventricular arrhythmia in 6 cases and supraventricular arrhythmia in 3 cases. There was no damage to the patent
grafts. Postoperative coronary angiography performed, in 8 cases revealed all the grafts to be patent without stenosis. Cardiac
symptoms were not found after the operation in any of the cases.Conclusions: These procedures can prevent the injury to patent grafts caused by a median sternotomy, and will be one of the useful strategies
for reoperative off-pump coronary artery bypass grafting. 相似文献
10.
A Nomoto 《Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan》1989,109(9):622-635
Molecular genetic studies of the antigenicity and the attenuation phenotype of type 1 poliovirus were described. Antigenic sites were identified on the genome of type 1 poliovirus by the determination of nucleotide sequence of the genome of variants that were not neutralized by the neutralizing monoclonal antibodies. The solution of the crystal structure of poliovirus revealed that all mutations found as above are located at the surface of the virion and cluster into three distinct sites. These regions probably represent distinct antibody binding sites. To study expression of the attenuation phenotype of type 1 poliovirus, a number of recombinant polioviruses were constructed in vitro by using infectious complementary deoxyribonucleic acid clones of the virulent Mahoney and attenuated Sabin 1 strains of type 1 poliovirus. Biological tests including a monkey neurovirulence test were performed on the recombinants. The results indicated that the 5' noncoding region harbors a relatively strong determinant influencing the attenuation. Further studies revealed that an adenine residue (Mahoney type) at nucleotide position 480 importantly contribute to the expression of the neurovirulence phenotype. However, a guanine residue (Sabin 1 type) at position 480 was not sufficient for full expression of the attenuation phenotype encoded by this genome region. These results suggested that the expression of the attenuation phenotype depends on the highly ordered structure formed in the 5' noncoding sequence and that the formation of such a structure is possibly influenced by the nucleotide position 480. To investigate the structure and function of the 5' noncoding region, many insertion and deletion sequences were introduced into the genome region. Replication processes of the mutants were analysed and second-site mutations in the genome of the variants that partially restored the phenotypes of the parental viruses were identified. The results indicated that interactions between different loci, for example at around positions 200 and 500, are important for maintaining the viral replication efficiency. 相似文献