全文获取类型
收费全文 | 4444篇 |
免费 | 243篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 54篇 |
妇产科学 | 51篇 |
基础医学 | 533篇 |
口腔科学 | 80篇 |
临床医学 | 191篇 |
内科学 | 1316篇 |
皮肤病学 | 50篇 |
神经病学 | 362篇 |
特种医学 | 89篇 |
外科学 | 1001篇 |
综合类 | 12篇 |
预防医学 | 90篇 |
眼科学 | 86篇 |
药学 | 193篇 |
中国医学 | 6篇 |
肿瘤学 | 525篇 |
出版年
2023年 | 49篇 |
2022年 | 80篇 |
2021年 | 116篇 |
2020年 | 74篇 |
2019年 | 114篇 |
2018年 | 137篇 |
2017年 | 112篇 |
2016年 | 126篇 |
2015年 | 116篇 |
2014年 | 180篇 |
2013年 | 185篇 |
2012年 | 341篇 |
2011年 | 301篇 |
2010年 | 159篇 |
2009年 | 138篇 |
2008年 | 247篇 |
2007年 | 256篇 |
2006年 | 260篇 |
2005年 | 257篇 |
2004年 | 248篇 |
2003年 | 222篇 |
2002年 | 194篇 |
2001年 | 71篇 |
2000年 | 71篇 |
1999年 | 86篇 |
1998年 | 56篇 |
1997年 | 44篇 |
1996年 | 28篇 |
1995年 | 22篇 |
1994年 | 32篇 |
1993年 | 21篇 |
1992年 | 48篇 |
1991年 | 53篇 |
1990年 | 34篇 |
1989年 | 34篇 |
1988年 | 29篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1972年 | 5篇 |
排序方式: 共有4727条查询结果,搜索用时 15 毫秒
51.
We cloned and determined the nucleotide sequences of cDNAs against nucleocapsid protein (NP) mRNA and the genomic RNA of human parainfluenza type 2 virus (PIV-2). The 3' terminal region of genomic RNA was compared among PIV-2, mumps virus (MuV), Newcastle disease virus (NDV), measles virus (MV), PIV-3, bovine parainfluenza type 3 virus (BPIV-3), Sendai virus (SV), and vesicular stomatitis virus (VSV), and an extensive sequence homology was observed between PIV-2 and MuV. Although no significant sequence relatedness was observed between PIV-2 and other viruses, the terminal four nucleotides were identical in the viruses compared, implying a specific role of these nucleotides on the replication of paramyxoviruses. A primer extension analysis elucidated the major NP mRNA initiation site with the sequence UCUAAGCC, which showed a moderate homology with the gene-starting consensus sequences of other paramyxoviruses. On the other hand, the NP mRNA was terminated at the nucleotide stretch AAAUUCUUUUU, and this sequence was conserved in all the PIV-2 genes, indicating that the oligonucleotides will form a part of the gene attenuation signal of PIV-2. Comparisons of NP protein sequence indicated a possible subgrouping of the paramyxoviruses into two groups, one of which is a group including PIV-2, PIV-4, MuV, and NDV, and another is a group including PIV-3, BPIV-3, and SV. This result supports an idea from our previous studies using polyclonal and monoclonal antibodies. Furthermore, our data indicated that the PIV-2 NP protein sequence was more closely related to MV and CDV than to other parainfluenza viruses, PIV-3 and SV. 相似文献
52.
Complete nucleotide sequence of the matrix gene of human parainfluenza type 2 virus and expression of the M protein in bacteria 总被引:2,自引:0,他引:2
M Kawano H Bando S Ohgimoto K Okamoto K Kondo M Tsurudome M Nishio Y Ito 《Virology》1990,179(2):857-861
The sequence of the M gene of human parainfluenza virus type 2 (PIV-2) has been determined. The sequence contained a large open reading frame with 1131 nucleotides encoding a protein with a calculated molecular weight of 42,312. Comparison of M protein sequence indicated that PIV-2 was more closely related to mumps virus and Newcastle disease virus than to other parainfluenza viruses, Sendai virus (SV), and parainfluenza virus type 3 (PIV-3), indicating a possible subdividing of the Paramyxovirus into two groups. This grouping is consistent with that obtained from analysis of the HN gene. Measles virus and canine distemper virus definitely belong to the subgroup composed of SV and PIV-3. No homology region was found in all the paramyxoviruses compared. However, a tertiary structure may be conserved in each subgroup of paramyxovirus. The M protein of PIV-2 was expressed in bacteria, and the product was recognized by a monoclonal antibody specific for the PIV-2 M protein. The bacterial-expressed protein, however, was heterogeneous and smaller in size. 相似文献
53.
Kanan Bando Toshinobu Kuroishi Hiroyuki Tada Takefumi Oizumi Yukinori Tanaka Tetsu Takahashi Itaru Mizoguchi Shunji Sugawara Yasuo Endo 《Journal of bone and mineral research》2021,36(9):1866-1878
Among the bisphosphonates (BPs), nitrogen-containing BPs (N-BPs) have much stronger anti–bone-resorptive actions than non-N–BPs. However, N-BPs have various side effects such as acute influenza-like reactions after their initial administration and osteonecrosis of the jawbones after repeated administration. The mechanisms underlying such effects remain unclear. To overcome these problems, it is important to profile the inflammatory nature of N-BPs. Here, we analyzed the inflammatory reactions induced in mouse ear pinnae by the N-BPs alendronate (Ale) and zoledronate (Zol). We found the following: (i) Ale and Zol each induced two phases of inflammation (early weak and late strong ear swelling); (ii) both phases were augmented by lipopolysaccharides (LPSs; cell-surface constituent of gram-negative bacteria, including oral bacteria), but prevented by inhibitors of the phosphate transporters of solute carrier 20/34 (SLC20/SLC34); (iii) macrophages and neutrophils were involved in both phases of Ale+LPS–induced ear-swelling; (iv) Ale increased or tended to increase various cytokines, and LPS augmented these effects, especially that on interleukin 1β (IL-1β); (v) adenosine triphosphate (ATP) was involved in both phases, and Ale alone or Ale+LPS increased ATP in ear pinnae; (vi) the augmented late-phase swelling induced by Ale+LPS depended on both IL-1 and neutrophil extracellular traps (NETs; neutrophil-derived net-like complexes); (vii) neutrophils, together with macrophages and dendritic cells, also functioned as IL-1β–producing cells, and upon stimulation with IL-1β, neutrophils produced NETs; (viii) stimulation of the purinergic 2X7 (P2X7) receptors by ATP induced IL-1β in ear pinnae; (ix) NET formation by Ale+LPS was confirmed in gingiva, too. These results suggest that (i) N-BPs induce both early-phase and late-phase inflammation via ATP-production and P2X7 receptor stimulation; (ii) N-BPs and LPS induce mutually augmenting responses both early and late phases via ATP-mediated IL-1β production by neutrophils, macrophages, and/or dendritic cells; and (iii) NET production by IL-1β–stimulated neutrophils may mediate the late phase, leading to prolonged inflammation. These results are discussed in relation to the side effects seen in patients treated with N-BPs. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
54.
Nishida Hayato Fukuhara Hiroki Nawano Takaaki Kanno Hidenori Yagi Mayu Yamagishi Atsushi Sakurai Toshihiko Naito Sei Kato Tomoyuki Kudo Kosuke Ichikawa Kazunobu Tsuchiya Norihiko 《Clinical and experimental nephrology》2021,25(12):1346-1353
Clinical and Experimental Nephrology - Arteriovenous fistula (AVF) is the most preferred vascular access for hemodialysis patients, and early failure of AVF is one of the most avoidable... 相似文献
55.
Imai Sojiro Ookawara Susumu Ito Kiyonori Hattori Takashi Fueki Mariko Iguchi Miho Kiryu Satoshi Sanayama Hidenori Kakei Masafumi Tabei Kaoru Morishita Yoshiyuki 《Journal of artificial organs》2023,26(2):127-133
Journal of Artificial Organs - Few reports have examined the association between changes in cerebral oxygenation and clinical factors, including blood pressure (BP), upon standing after... 相似文献
56.
Ueda M Psarras K Jinno H Ikeda T Enomoto K Kitajima M Futami J Yamada H Seno M 《Breast cancer (Tokyo, Japan)》1997,4(4):253-255
Recombinant human ribonuclease 1 (RNasel) was chemically linked to recombinant human epidermal growth factor (EGF). The cytotoxicity
of this conjugate was assayed using MTT assay. The EGF-RNase conjugate showed dose-dependent cytotoxicity against breast and
squamous cell carcinomas overexpressing the EGF receptor (EGFR). The cytotoxicity of the conjugate correlated positively with
the level of EGFR expression by each cell line. These results suggest that the EGF-RNase conjugate is a more effective anticancer
agent with less immunogenicity and toxicity than conventional chimeric breast cancer toxins. 相似文献
57.
Bando T Kasahara K Shibata K Numata Y Heki U Shirasaki H Iwasa K Fujimura M Matsuda T 《International journal of oncology》1995,7(4):789-793
3-Hydroxymethyl-5-aziridinyl-1-methyl-[1H-indole-4,7-dione]-prop-beta-en -alpha-ol (EO9) is a bioreductive anticancer agent active for non-small cell lung cancer (NSCLC) and structurally related to mitomycin C (MMC). DT-diaphorase (DTD) is regarded as a two electron reductase that plays an important role in the biotransformation of MMC to antitumor metabolites. To evaluate the role of DTD as a bioactivator of EO9 in NSCLC cell lines under oxic and hypoxic conditions, we examined the inhibitory effect of dicumarol which was regarded as a selective inhibitor of DTD on the sensitivity to EO9 in vitro. In this study, we used an MMC-resistant NSCLC cell line (PC-9/MC4) which was established from a PC-9 cell line as a parent cell line by continuous exposure to MMC in our laboratory. We reported previously that the subline PC-9/MC4 was 6.7-fold more resistant to MMC than PC-9 with decreased DTD activity. The IC50 value of PC-9 against EO9 was significantly increased by co-incubation with dicumarol under oxic conditions. EO9 was more cytotoxic against PC-9/MC4 than against PC-9 cells and the enhancement was impaired by tempol under hypoxic conditions. These findings suggest a suppressive role of DTD against one-electron reduction pathway in the bioactivation of EO9 under hypoxic conditions and EO9 may be more active against oxygen-deficient solid tumors especially in MMC-resistant NSCLC cells with low levels of DTD activity. 相似文献
58.
The results of surgical treatment for a ruptured type B aortic dissection remain far from satisfactory. It is believed that
additional perfusion from the right axillary artery might be more beneficial than perfusion from only the femoral artery during
surgery for a ruptured thoracic aneurysm. The right axillary perfusion is more likely to perfuse the vital organs proximal
to the ruptured area, and thus avoid retrograde emboli. In addition, if the open proximal method is performed, then the right
axillary perfusion is able to facilitate the evacuation of air from the aortic lumen. We present herein the case of a patient
in whom a ruptured type B acute aortic dissection was successfully treated by applying right axillary perfusion through a
left thoracotomy. 相似文献
59.
Finger bougie method compared with pyloroplasty in the gastric replacement of the esophagus 总被引:2,自引:0,他引:2
Yamashita Y Hirai T Mukaida H Yoshimoto A Kuwahara M Inoue H Toge T 《Surgery today》1999,29(2):107-110
To elucidate the necessity of pyloroplasty for the gastric tube through the posterior mediastinum in esophageal surgery, gastric
emptying and duodenogastric reflux (DGR) were evaluated in 16 cases undergoing an anterior pylorectomy (group P) and in 16
cases treated by the finger bougie method (group F). First, the obstruction and reflux symptoms were examined based on a patient
questionnaire using a brief scoring system. The median value of the symptom score showed the patients in P to have more symptoms
than those in F; however, the difference was not significant (8.0 vs 6.0). Secondly, the swallowed Tc O4
− (85 MBq) was counted using a gamma camera at three sites on the sternal bone in the upright position based on a gastric transit
scintigram. Both the descending time of the RI peak and the clearance rates were similar between the two groups. Thirdly,
intragastric 24-h pH monitoring was carried out. Antimony pH sensors were anchored 5 and 15 cm below the esophagogastrostomy.
We could not find any difference between the two groups in both the % time pH>4 and %time pH>7. These findings thus revealed
no big difference between groups P and F. The finger bougie method to drain the vagotomized posterior mediastinal stomach
was found to achieve results similar to conventional pyloroplasty, while it was also simpler and safer. 相似文献
60.
Inagaki M Yabuki H Hashimoto M Maguchi M Kino S Sawa M Ojima H Tokusashi Y Miyokawa N Kusano M Kasai S 《Surgery today》1999,29(12):1260-1263
We describe herein the case of a 51-year-old woman in whom metastatic tumor seeding of the percutaneous transhepatic biliary
drainage tract occurred following a pancreatoduodenectomy for carcinoma of the distal common bile, duct. An abdominal computed
tomography scan done 6 months after the initial operation detected a hepatic lesion located at the site of the previous percutaneous
transhepatic biliary drainage tract. Implantation of bile duct carcinoma in the drainage tract was diagnosed, and the recurrent
tumor was successfully resected by performing a subsegmentectomy of segment 3 and removal of the adjacent abdominal wall.
At present, 5 years and 4 months after the second resection, the patient is in good health without any signs of recurrence.
This case report demonstrates that an aggressive surgical approach should be performed for tumor seeding of a transhepatic
biliary catheter tract. 相似文献