全文获取类型
收费全文 | 19849篇 |
免费 | 1062篇 |
国内免费 | 144篇 |
专业分类
耳鼻咽喉 | 164篇 |
儿科学 | 312篇 |
妇产科学 | 378篇 |
基础医学 | 2777篇 |
口腔科学 | 313篇 |
临床医学 | 1219篇 |
内科学 | 5229篇 |
皮肤病学 | 441篇 |
神经病学 | 1258篇 |
特种医学 | 881篇 |
外科学 | 3621篇 |
综合类 | 103篇 |
预防医学 | 504篇 |
眼科学 | 248篇 |
药学 | 1309篇 |
4篇 | |
中国医学 | 50篇 |
肿瘤学 | 2244篇 |
出版年
2023年 | 131篇 |
2022年 | 226篇 |
2021年 | 456篇 |
2020年 | 236篇 |
2019年 | 313篇 |
2018年 | 387篇 |
2017年 | 330篇 |
2016年 | 434篇 |
2015年 | 449篇 |
2014年 | 546篇 |
2013年 | 626篇 |
2012年 | 1084篇 |
2011年 | 1207篇 |
2010年 | 633篇 |
2009年 | 616篇 |
2008年 | 1064篇 |
2007年 | 1258篇 |
2006年 | 1202篇 |
2005年 | 1155篇 |
2004年 | 1161篇 |
2003年 | 1174篇 |
2002年 | 1090篇 |
2001年 | 459篇 |
2000年 | 422篇 |
1999年 | 441篇 |
1998年 | 317篇 |
1997年 | 260篇 |
1996年 | 198篇 |
1995年 | 193篇 |
1994年 | 131篇 |
1993年 | 161篇 |
1992年 | 261篇 |
1991年 | 199篇 |
1990年 | 237篇 |
1989年 | 234篇 |
1988年 | 239篇 |
1987年 | 194篇 |
1986年 | 170篇 |
1985年 | 145篇 |
1984年 | 124篇 |
1983年 | 101篇 |
1982年 | 49篇 |
1980年 | 45篇 |
1979年 | 64篇 |
1978年 | 47篇 |
1977年 | 49篇 |
1974年 | 48篇 |
1973年 | 54篇 |
1972年 | 45篇 |
1970年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
Sadahiro Hijikata Igen Hongo Shu-ichi Nakayama Tetsuo Yamaguchi Yoshiyuki Sekikawa Toshihiro Nozato Takashi Ashikaga 《The Canadian journal of cardiology》2019,35(1):104.e9-104.e11
Syphilis is a sexually transmitted disease caused by Treponema pallidum. Syphilitic aortitis might coexist in a dysfunctional aortic valve, but the etiology remains unclear, because microbiological diagnosis is difficult. A 62-year-old man with low-grade fever was diagnosed with aortitis and infective endocarditis, due to Treponema pallidum infection, using polymerase chain reaction analysis. This case suggests that syphilis might cause infective endocarditis. 相似文献
4.
Yuzuru Takemura Haku Ishida Yuji Inoue 《Clinical chemistry and laboratory medicine》2003,41(5):668-674
Few studies have demonstrated the optimal usage of common inflammatory markers, alone or in combination, based on the cost-effectiveness. We analyzed the yield and cost of C-reactive protein (CRP), white blood cell count (WBC), erythrocyte sedimentation rate (ESR), sialic acid, and protein fractionation in 177 new primary care outpatients with inflammation-related symptoms. A useful result (UR) was assigned if tests contributed to a change in physician's diagnosis or decision-making. Costs of testing were calculated based on either single or simultaneous measurement. Five inflammatory markers generated 147 URs in 123 patients. CRP showed the best contribution to generation of UR, followed by sialic acid, protein fractionation, WBC, and ESR. CRP demonstrated poor correlation with WBC (r = 0.458), while sialic acid strongly correlated with total absolute amount of alpha1 and alpha2 fractions in protein fractionation (r = 0.855) and moderately with ESR (r = 0.651). The combination of CRP and WBC produced the best cost-effectiveness at a cost of Yen 1169 (US dollars 9.6 or Euro 9.7)/additional UR against CRP testing alone. Sialic acid, an automated multichannel analyzer-based test, demonstrated the favorable cost-effectiveness over ESR or protein fractionation when combined with CRP (and WBC). Our results indicate that the optimal usage of these inflammatory markers should involve careful cost-effectiveness considerations. 相似文献
5.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy. 相似文献
6.
Yuji Morimoto Osamu Kemmotsu Koichi Kitami Izumi Matsubara Ichiro Tedo 《Journal of anesthesia》1995,9(1):22-26
We evaluated whether we could predict the neurologic outcome in 55 out-of-hospital cardiac arrest patients using auditory
brainstem responses (ABR). ABR patterns were classified into one of 3 types by evaluation of 5 components: type 1, with all
5 components; type 2, lack of at least one response between the 2nd and 5th components; type 3, with only the first component
or no response. The relation between the ABR patterns on the 3rd day following resuscitation and the neurologic outcome on
hospital discharge was evaluated. The specificity that the 5 awake patients had type-1 ABR was 38%. The sensitivity that the
10 brain dead patients had type-3 ABR was 60%. In the type-1 ABR patients, the negative predictive value that the patients
were awake was 100%. In the type-3 ABR patients, the negative predictive value that the patients became brain dead was 90.9%.
These results suggest that ABR on the 3rd post-resuscitation day may not be useful for predicting if patients are awake or
become brain dead, although the loss of components may be a sign of morbidity, and the presence of the 2nd or later components
indicates possible future prevention of brain death. 相似文献
7.
Akira Sezai Motomi Shiono Mitsumasa Hata Akira Saito Tsutomu Hattori Shinji Wakui Masao Soeda Yuji Kasamaki Kohtaro Tokai Satoshi Saito Nanao Negishi Yukiyasu Sezai 《Annals of thoracic and cardiovascular surgery》2005,11(6):413-415
The Carpentier-Edwards pericardial bioprosthesis has been markedly improved in the long-term results and valve-related complications including valve dysfunction, compared to the previous generation bioprosthesis. We report a patient in whom transient prosthetic valve regurgitation and hemolysis occurred early after mitral valve replacement using a Carpentier-Edwards pericardial bioprosthesis and were resolved by preservative therapy. The patient was a 77-year-old female diagnosed with severe mitral valve stenosis and insufficiency. She underwent mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. Opening and closing of the three leaflets looked good on intraoperative transesophageal echocardiography (TEE). The only prosthetic valve regurgitation was evident at the central region where the leaflets form coaptation, and no abnormal findings were seen. Serum lactate dehydrogenase (LDH) was decreased to 405 U/l after surgery. However, LDH again began to increase on the 3rd day after surgery and it increased to 1,830 U/l on the 14th day after surgery. Hemolytic urine was detected on 10th day after surgery. PVL was not detected, but moderate abnormal regurgitation from the outside of the stent pocket was detected on TEE. Revision of valve replacement was considered, but LDH thereafter to 393 U/l on 41st day after surgery. The TEE was repeated, and only a trace of central jet was detected without abnormal regurgitation, unlike the previous examination. The patient did not develop any complications thereafter and was discharged on 47th day after surgery. LDH was nearly normal at the time of discharge. 相似文献
8.
9.
Yuji Masuda Toyonobu Yamashita Tetsuji Hirao Motoji Takahashi 《Skin research and technology》2009,15(2):224-229
Background/purpose: It is crucial to establish an accurate method for measuring skin pigmentation in cosmetic science and clinical dermatology. Here, we report a non-invasive precise method for measuring skin melanin content.
Methods: In order to determine the concentrations of melanin and hemoglobin in skin, we used the spectrum resolution (SR) method. In brief, the absorption spectrum of the skin was calculated from the reflection spectrum using a spectrophotometer. The concentrations of melanin and hemoglobin were then determined using a multiple regression analysis, assuming that the absorption spectrum of the skin is expressed as a linear summation of the absorptions of melanin and hemoglobin according to the Lambert–Beer law. The skin changes in the volar forearm, which had been irradiated by ultraviolet rays (UV), were observed daily by the SR method.
Results: A multiple regression analysis with an absorption spectrum of 500–700 nm was performed. The multiple correlation coefficient was 0.993, resulting in a satisfactory precise estimate of the concentrations of melanin. After UV irradiation, the concentration of melanin monitored by the SR method increased until 8 days and decreased gradually afterwards.
Conclusions: The SR method allows the evaluation of the changes of epidermal melanin induced by UV irradiation. 相似文献
Methods: In order to determine the concentrations of melanin and hemoglobin in skin, we used the spectrum resolution (SR) method. In brief, the absorption spectrum of the skin was calculated from the reflection spectrum using a spectrophotometer. The concentrations of melanin and hemoglobin were then determined using a multiple regression analysis, assuming that the absorption spectrum of the skin is expressed as a linear summation of the absorptions of melanin and hemoglobin according to the Lambert–Beer law. The skin changes in the volar forearm, which had been irradiated by ultraviolet rays (UV), were observed daily by the SR method.
Results: A multiple regression analysis with an absorption spectrum of 500–700 nm was performed. The multiple correlation coefficient was 0.993, resulting in a satisfactory precise estimate of the concentrations of melanin. After UV irradiation, the concentration of melanin monitored by the SR method increased until 8 days and decreased gradually afterwards.
Conclusions: The SR method allows the evaluation of the changes of epidermal melanin induced by UV irradiation. 相似文献
10.
M Nakayama Y Takahashi H Itoh K Kamiya M Shiratsuchi G Otani 《The Journal of antibiotics》1989,42(11):1535-1540
Two antifungal antibiotics maniwamycins A and B were isolated from the culture broth of a strain of actinomycetes, which were classified as Streptomyces prasinopilosus. These antibiotics were isolated by resin absorption and extraction with EtOAc and purified by column chromatography. Both antibiotics were found to be new azoxy substances from their physico-chemical properties. They showed broad antifungal spectra. 相似文献