全文获取类型
收费全文 | 9328篇 |
免费 | 435篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 144篇 |
儿科学 | 128篇 |
妇产科学 | 89篇 |
基础医学 | 1000篇 |
口腔科学 | 215篇 |
临床医学 | 695篇 |
内科学 | 2431篇 |
皮肤病学 | 176篇 |
神经病学 | 691篇 |
特种医学 | 419篇 |
外科学 | 1609篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 404篇 |
眼科学 | 165篇 |
药学 | 503篇 |
中国医学 | 10篇 |
肿瘤学 | 1096篇 |
出版年
2023年 | 94篇 |
2022年 | 169篇 |
2021年 | 304篇 |
2020年 | 150篇 |
2019年 | 195篇 |
2018年 | 237篇 |
2017年 | 168篇 |
2016年 | 195篇 |
2015年 | 218篇 |
2014年 | 295篇 |
2013年 | 311篇 |
2012年 | 538篇 |
2011年 | 616篇 |
2010年 | 340篇 |
2009年 | 254篇 |
2008年 | 473篇 |
2007年 | 560篇 |
2006年 | 531篇 |
2005年 | 620篇 |
2004年 | 586篇 |
2003年 | 540篇 |
2002年 | 489篇 |
2001年 | 126篇 |
2000年 | 140篇 |
1999年 | 143篇 |
1998年 | 96篇 |
1997年 | 73篇 |
1996年 | 91篇 |
1995年 | 70篇 |
1994年 | 49篇 |
1993年 | 44篇 |
1992年 | 81篇 |
1991年 | 79篇 |
1990年 | 63篇 |
1989年 | 101篇 |
1988年 | 106篇 |
1987年 | 72篇 |
1986年 | 68篇 |
1985年 | 74篇 |
1984年 | 42篇 |
1983年 | 48篇 |
1982年 | 31篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 41篇 |
1974年 | 24篇 |
1972年 | 22篇 |
1971年 | 29篇 |
1969年 | 23篇 |
1968年 | 30篇 |
排序方式: 共有9823条查询结果,搜索用时 15 毫秒
71.
N. Adachi M. Migita T. Ohta A. Higashi I. Matsuda 《European journal of pediatrics》1997,156(6):444-448
Natural Killer (NK) cell activity was examined in a 16-month-old Japanese boy with Shwachman syndrome associated with severe
vitamin E deficiency. As evaluated by 51Cr-release assay from K562 cells, NK cell activity was constantly decreased. After 8 weeks of oral α-tocopherol (α-Toc) supplementation
(100 mg/day), NK cell activity had normalised. When α-Toc supplementation was interrupted for 16 weeks, NK cell activity again
decreased. Flow cytometry of peripheral lymphocytes revealed a lowered number of CD16+ CD 56− fraction, which has the most potent NK cell activity. Single cell-in-agarose assay, to investigate the binding and cytolytic
activity of NK cell at the single cell level, revealed that the number of NK cells which bind to K562 cell was decreased,
but that the cytolytic activity of the individual binding cell was relatively unaffected. A second supplementation of α-Toc
for 8 weeks successfully restored NK cell activity, the number of cells expressing NK cell markers and the number of K562-binding
cells as compared to the age-matched normal range.
Conclusion These results indicate that severe vitamin E deficiency caused impaired NK cell activity due to a decrease in the number
of CD16+ CD56− NK cells and that this abnormality is reversible with α-Toc supple‐mentation.
Received: 30 January 1996 and in revised form: 19 November 1996 / Accepted: 22 November 1996 相似文献
72.
Therapeutic Value of Neoadjuvant Intra-arterial Chemotherapy (Cisplatin) and Irradiation for Locally Advanced Uterine Cervical Cancer 总被引:1,自引:0,他引:1
Takafumi Toita Kaoru Sakumoto Masahiro Higashi Kazuhiko Ogawa Yasumasa Kakinohana Sanae Shinzato Hidehiko Moromizato Koji Kanazawa Satoshi Sawada 《Gynecologic oncology》1997,65(3):421-424
We analyzed long-term treatment results in 51 patients with locally advanced uterine cervical carcinoma (IIB, 4; IIIB, 43; IVA, 4) treated with neoadjuvant intra-arterial (I-A) chemotherapy (cisplatin) via the uterine artery and irradiation. Thirty patients (58.8%) developed recurrence. Twelve had pelvic recurrence alone, 8 had distant metastases alone, and 10 had both pelvic and distant failure. The 5-year cumulative pelvic control rate, absolute survival rate, and disease-free survival rate were 55.3, 47.1, and 39.4%, respectively. Eight of 51 patients (15.7%) suffered late complications. These results suggest that our neoadjuvant I-A chemotherapy prior to irradiation has limited additional value for long-term prognosis in patients with locally advanced uterine cervical carcinoma. 相似文献
73.
Daisuke Abe Toshiyuki Sakaki Tatsuya Kusudo Atsushi Kittaka Nozomi Saito Yoshitomo Suhara Toshie Fujishima Hiroaki Takayama Hiromi Hamamoto Masaki Kamakura Miho Ohta Kuniyo Inouye 《Drug metabolism and disposition》2005,33(6):778-784
Recently, we demonstrated that some A-ring-modified vitamin D3 analogs had unique biological activity. Of these analogs, 2alpha-propoxy-1alpha,25(OH)2D3 (C3O1) and 2alpha-(3-hydroxypropoxy)-1alpha,25(OH)2D3 (O2C3) were examined for metabolism by CYP27A1 and CYP24A1. Surprisingly, CYP27A1 catalyzed the conversion from C3O1 to O2C3, which has 3 times more affinity for vitamin D receptor than C3O1. Thus, the conversion from C3O1 to O2C3 by CYP27A1 is considered to be a metabolic activation process. Five metabolites were detected in the metabolism of C3O1 and O2C3 by human CYP24A1 including both C-23 and C-24 oxidation pathways. On the other hand, three metabolites of the C-24 oxidation pathway were detected in their metabolism by rat CYP24A1, indicating a species-based difference in the CYP24A1-dependent metabolism of C3O1 and O2C3 between humans and rats. Kinetic analysis revealed that the Km and kcat values of human CYP24A1 for O2C3 are, respectively, approximately 16 times more and 3 times less than those for 1alpha,25(OH)2D3. Thus, the catalytic efficiency, kcat/Km, of human CYP24A1 for O2C3 is only 2% of 1alpha,25(OH)2D3. These results and a high calcium effect of C3O1 and O2C3 in animal experiments using rats suggest that C3O1 and O2C3 are promising for clinical treatment of osteoporosis. 相似文献
74.
Allylnitrile and crotononitrile induce behavioral abnormalities in mice. To explore the possible involvement of the vestibular system in these behavioral abnormalities, the expression of Fos protein, used as an indicator of neuronal activity, was examined within various brain structures in allylnitrile-, crotononitrile- and vehicle-treated mice. In each nitrile-treated mouse, Fos expression was observed in brain structures, which were divided into two groups. The structures in group 1 showed Fos expression between 1.5 h and 2 days postdosings, and in those in group 2 expression remained for up to 30 days postdosing. As most of these structures, especially in group 2, were identical to some Fos-positive structures observed after unilabyrinthectomy, the present results indicate that each nitrile induces Fos expression by causing a change in the peripheral vestibular system, resulting in behavioral abnormalities. 相似文献
75.
Wang L Kuroiwa Y Kamitani T Li M Takahashi T Suzuki Y Shimamura M Hasegawa O 《Journal of neurology》2000,247(5):356-363
To determine whether there are characteristic changes in event-related potentials (ERPs) in parkinsonian syndromes we studied
8 patients with progressive supranuclear palsy (PSP), 10 patients with corticobasal degeneration (CBD), 9 patients with striatonigral
degeneration (SND), and 16 patients with idiopathic Parkinson's disease (PD) with a mean duration of illness shorter than
5 years in each group. A visual oddball paradigm was employed to elicit P300. P300 to the rare target and rare nontarget stimuli
and reaction time (RT) to rare target stimuli in each group were compared with those in the corresponding age-matched normal
control group and to each other after age correction. The correlation of P300 and RT to motor disability score was also studied.
In PSP P300 amplitude was markedly reduced while in CBD P300 latency was prolonged. P300 amplitude to rare nontargets in SND
and PD was attenuated. The mean RT in the PSP and the CBD group was significantly longer than in the other two groups. The
mean RT in PD and P300 amplitude to rare nontargets in both CBD and PD showed significant correlation with the severity of
motor disability. Simultaneous measurement of P300 and RT may yield useful supplementary information in facilitating diagnosis
of parkinsonian syndromes in addition to clinical criteria.
Received: 6 April 1999, Received in revised form: 5 August 1999, Accepted: 12 January 2000 相似文献
76.
Masakatsu Fujinoki Tatsuya Suzuki Takeshi Takayama Hiroaki Shibahara Hideki Ohtake 《Reproductive Medicine and Biology》2006,5(2):123-135
Background and Aims It has been widely accepted that sperm hyperactivation is regulated by protein phosphorylations. But, the sperm hyperactivation
phosphorylation pathway is not well understood yet because several different proteins have been detected in other studies.
In order to understand the phosphorylation pathway that regulates hyperactivation, we established how to extract sperm protein
completely and detected proteins that were phosphorylated during hyperactivation.
Methods Protein phosphorylation of hamster spermatozoa was detected by western blotting using antiphospho-amino acid monoclonal antibodies
or the SELDI ProteinChip system with IMAC-Ga(III).
Results We detected 75 protein/peptide phosphoryations using the method established in the present study. Tyrosine phosphorylations
occurred during hyperactivation. Serine or threonine phosphorylations occurred for 30 min. Furthermore, four of the serine
or threonine phosphorations were phosphorylated by A-kinase. As for peptides, 15 peptides were dephosphorylated for 30 min.
Other peptides were phosphorylated during hyperactivation.
Conclusions Because most of the proteins detected in the present study have been described previously, we could detect comprehensive protein
phosphorylations. Moreover, we also detected many novel phosphopeptides. Although we did not understand the role of peptide,
it was likely that motility was basically regulated by serine/threonine phosphorylations and hyperactivation was mainly regulated
by tyrosine phosphorylations. (Reprod Med Biol 2006; 5: 123–135) 相似文献
77.
Yuji Komorita Toshiaki Ohkuma Masanori Iwase Hiroki Fujii Hitoshi Ide Yutaro Oku Taiki Higashi Ayaka Oshiro Wakako Sakamoto Masahito Yoshinari Udai Nakamura Takanari Kitazono 《Journal of diabetes investigation.》2022,13(6):1030
Aims/IntroductionThe evidence regarding the effects of coffee consumption on incident chronic kidney disease is inconclusive, and no studies have investigated the relationship in patients with diabetes. We aimed to prospectively investigate the relationship between coffee consumption and the decline in estimated glomerular function rate (eGFR) in patients with type 2 diabetes.Materials and MethodsA total of 3,805 patients (2,112 men, 1,693 women) with type 2 diabetes (mean age 64.2 years) and eGFR ≥60 mL/min/1.73 m2 were followed (completion of follow up, 97.6%; median 5.3 years). Coffee consumption was assessed at baseline. The end‐point was a decline in eGFR to <60 mL/min/1.73 m2 during the follow‐up period.ResultsDuring follow up, 840 participants experienced a decline in eGFR to <60 mL/min/1.73 m2. Higher coffee consumption reduced the risk of decline in eGFR. Compared with no coffee consumption, the multivariate‐adjusted hazard ratios (95% confidence intervals) were 0.77 (0.63–0.93) for less than one cup per day, 0.77 (0.62–0.95) for one cup per day and 0.75 (0.62–0.91) for two or more cups per day (P for trend 0.01). This trend was unaffected by further adjustment for baseline eGFR and albuminuria. The mean eGFR change per year was −2.16 mL/min/1.73 m2 with no coffee consumption, −1.89 mL/min/1.73 m2 with less than one cup per day, −1.80 mL/min/1.73 m2 with one cup per day and −1.78 mL/min/1.73 m2 with two or more cups per day (P for trend 0.03).ConclusionsCoffee consumption is significantly associated with a lower risk of decline in eGFR in patients with type 2 diabetes. 相似文献
78.
Otake K Suzuki H Higashi R Yabuuchi H Haga M Maeda T Cook TJ Tamai I 《Journal of pharmaceutical sciences》2008,97(5):1821-1830
Intestinal membrane permeability is an important factor affecting the bioavailability of drugs. As a strategy to improve membrane permeability, membrane transporters are useful targets since essential nutrients are absorbed efficiently via specific transporters. For example, there are reports that intestinal hexose transporters could be used as a tool to improve permeability; however, there has been no direct evidence that the transporter protein, sodium/glucose cotransporter 1 (SGLT1), is involved in the transport of hexose analogs. Accordingly, we examined directly whether the intestinal membrane permeability of hexose analogs can be improved by utilizing SGLT1. Three hexose-quinoline derivatives were synthesized and their interactions with SGLT1 were evaluated. Among the three derivatives, the glucose-quinoline molecule exhibited an inhibitory effect on D-glucose uptake by both rat intestinal brush-border membrane vesicles (BBMVs) and Xenopus oocytes expressing SGLT1. In addition, significant uptake of the glucose-quinoline derivative by Xenopus oocytes expressing SGLT1 was observed by both an electrophysiological assay and direct measurement of the uptake of the compound, while the galactose-quinoline derivative did not show significant uptake via SGLT1. Thus, it was directly demonstrated that SGLT1 could be used as a tool for the improvement of intestinal membrane permeability of drugs by modification to the glucose analogs. 相似文献
79.
Amano S Mimura T Yamagami S Osakabe Y Miyata K 《Japanese journal of ophthalmology》2005,49(6):448-452
Purpose
To examine the properties of corneas tissue-engineered with cultured human corneal endothelial cells (HCEC) and human corneal stroma.Methods
Primary HCEC cultures were established from endothelial cell layer explants and propagated on culture dishes coated with bovine corneal endothelial extracellular matrix. A cell suspension of HCEC at the fifth passage was transferred onto human corneal stroma deprived of endothelial cells, and the corneas were gently centrifuged to enhance cell attachment. The cell density of the tissue-engineered corneas was examined after staining with alizarin red and trypan blue. The tissue-engineered corneas were histologically examined by light and electron microscopy. The pump function of the tissue-engineered corneas was measured using an Ussing chamber.Results
The mean endothelial cell density of four tissue-engineered corneas was 2380 ± 264 cells/mm2 (mean ± SD). HCEC on the tissue-engineered corneas had a morphology similar to HCEC in vivo. The pump function parameters of the tissue-engineered corneas were 55%–75% of those of normal corneas.Conclusions
HCEC on the tissue-engineered corneas have morphology and cellular density similar to HCEC in vivo, whereas the pump function of the tissue-engineered corneas was lower than in normal corneas. Jpn J Ophthalmol 2005;49:448–452 © Japanese Ophthalmological Society 2005 相似文献80.
A zinc balance study was conducted on low birth weight infants (670 to 2420 g) fed unsupplemented human milk (the mother's or pooled) (group 1, n = 17) or human milk with zinc supplementation (group 2, n = 17). The mean zinc concentrations of the diets in groups 1 and 2 were 2.2 +/- 1.1 mg/L and 8.4 +/- 0.8 mg/L, respectively, and the mean copper concentration of the diets in both groups was 0.45 +/- 0.12 mg/L. The studies were performed 7 to 128 days after birth, which corresponded to 29 to 43 weeks postconceptional age. The turning point of zinc balance from negative to positive appeared to be greatly influenced by the postconceptional age, being approximately 36 weeks in both group 1 and group 2, rather than other factors such as the zinc intake and the postnatal age. The calculated minimal requirement of dietary zinc during the period from 36 to 40 weeks postconceptional age, for an adequate amount of zinc retention in infants (250 micrograms/kg/d), was 0.8 mg/kg/d. Zinc supplementation did not appear to interfere with copper retention. 相似文献