全文获取类型
收费全文 | 42702篇 |
免费 | 2038篇 |
国内免费 | 210篇 |
专业分类
耳鼻咽喉 | 336篇 |
儿科学 | 771篇 |
妇产科学 | 670篇 |
基础医学 | 5549篇 |
口腔科学 | 1049篇 |
临床医学 | 2829篇 |
内科学 | 10547篇 |
皮肤病学 | 665篇 |
神经病学 | 2994篇 |
特种医学 | 1545篇 |
外科学 | 8118篇 |
综合类 | 198篇 |
预防医学 | 1348篇 |
眼科学 | 491篇 |
药学 | 3076篇 |
中国医学 | 132篇 |
肿瘤学 | 4632篇 |
出版年
2023年 | 207篇 |
2022年 | 406篇 |
2021年 | 728篇 |
2020年 | 425篇 |
2019年 | 574篇 |
2018年 | 737篇 |
2017年 | 573篇 |
2016年 | 677篇 |
2015年 | 757篇 |
2014年 | 998篇 |
2013年 | 1180篇 |
2012年 | 1872篇 |
2011年 | 1982篇 |
2010年 | 1117篇 |
2009年 | 935篇 |
2008年 | 1761篇 |
2007年 | 1911篇 |
2006年 | 1919篇 |
2005年 | 2013篇 |
2004年 | 2014篇 |
2003年 | 1949篇 |
2002年 | 1962篇 |
2001年 | 1699篇 |
2000年 | 1646篇 |
1999年 | 1590篇 |
1998年 | 593篇 |
1997年 | 505篇 |
1996年 | 425篇 |
1995年 | 387篇 |
1994年 | 372篇 |
1993年 | 336篇 |
1992年 | 1013篇 |
1991年 | 960篇 |
1990年 | 829篇 |
1989年 | 925篇 |
1988年 | 781篇 |
1987年 | 715篇 |
1986年 | 755篇 |
1985年 | 693篇 |
1984年 | 449篇 |
1983年 | 387篇 |
1982年 | 209篇 |
1981年 | 202篇 |
1979年 | 314篇 |
1978年 | 247篇 |
1977年 | 212篇 |
1975年 | 212篇 |
1974年 | 190篇 |
1973年 | 174篇 |
1971年 | 177篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
Takayoshi Owada Kentaro Takahashi Yasuhiko Kita 《Modern rheumatology / the Japan Rheumatism Association》2009,19(5):573-580
We report 51- and 43-year-old Japanese female patients with systemic lupus erythematosus (SLE) associated with subarachnoid
hemorrhage (SAH) due to rupture of intracranial saccular aneurysms. We also review the literature of Japanese SLE patients
with SAH. SAH in Japanese SLE patients is more frequent than in patients from Western countries, has different features from
the general population, and can occur regardless of SLE disease activity. Clinicians must pay attention to SAH in all SLE
patients. 相似文献
23.
H. Kurokawa M. Zhang S. Matsumoto Y. Yamashita T. Tomoyose T. Tanaka H. Fukuyama T. Takahashi 《Journal of oral pathology & medicine》2005,34(6):329-333
BACKGROUND: Although many histopathologic factors in squamous cell carcinoma of the tongue predict the prognosis, the major predictive factors have not been identified clearly. This study analyzed the prognostic value of the histologic grade at the deep invasive front of tongue squamous cell carcinoma. METHODS: The clinicopathologic features of 124 consecutive patients seen between January 1985 and December 1999 with previously untreated squamous cell carcinoma of the tongue were reviewed. Their mean age was 58.5 years (range: 23-90) and the male-female ratio was 1.8: 1 (79 men and 45 women). There were 41, 40, 30, and 13 cases at stage I to stage IV, respectively. The clinicopathologic factors, especially the histologic grade at the deep invasive front (invasive front grade, IFG), were analyzed to determine factors predicting prognosis. RESULTS: The 5-year disease-free survival rate of the patients treated with curative aim only was 66.7%. Clinicopathologic factors significantly associated with the prognosis were T classification, tumor size, stage classification, tumor depth, macroscopic appearance, cervical lymph node metastasis (nodal metastasis), microvascular invasion, and IFG. In a multivariate analysis, patients with tumor depth >/=4 mm, IFG >/=8 points, and nodal metastasis had a reduced disease-free survival and IFG >/=11 points had a predictive value for nodal metastasis (odds ratio: 7.34; P = 0.0019). CONCLUSION: This study found that a high IFG malignancy score had a high prognostic value for squamous cell carcinoma of the tongue. 相似文献
24.
The estimation of breakthrough time for multicomponent organic solvent vapors on activated carbon fixed beds is significantly complicated and difficult. This paper describes a simple estimation method of breakthrough time for the first component (foremost breakthrough component) in two- or three-component organic solvent vapors on an activated carbon fixed bed. The breakthrough time for the first component was expressed by the harmonic mean value of the breakthrough times in each pure component. Estimated breakthrough times were compared with the experimental ones. 相似文献
25.
Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice 总被引:2,自引:0,他引:2
To compare nerve regeneration in young adult and aging mice, the right sciatic nerves of 6- and 24-month-old mice were crushed at the sciatic notch. Two weeks later, both groups of mice were perfused with an aldehyde solution, and, after additional fixation, the sciatic nerves were processed so that the transverse sections of each nerve subsequently studied by light and electron microscopy included the entire posterior tibial fascicle 5 mm distal to the crush site. The same level was sectioned in unoperated contralateral nerves; these nerves served as controls. Electron micrographs and the Bioquant Image Analysis System IV were used to measure areas of posterior tibial fascicles and count the number of myelinated axons, the number of unmyelinated axons, and their frequency in Schwann cell units. In aging mice, the total number of regenerating myelinated axons was significantly reduced, but totals of regenerating unmyelinated axons in aging and young adults did not differ significantly. In aging mice, the frequency of Schwann cells that contained a single unmyelinated axon was greater, suggesting that before myelination began, Schwann cell ensheathment of axons also was slowed. After axotomy by a crush injury, the area of the posterior tibial fascicle was less than that in young adults and the distal disintegration of myelin sheath remnants also appeared to be retarded. The results indicate that responses of neurons, axons, and Schwann cells could be important in slowing the regeneration of myelinated fibers found in sciatic nerves from aging mice. 相似文献
26.
The anti-allergic activity of bryonolic acid (1) isolated from the cultured cells of Luffa cylindrica L. (Cucurbitaceae) was compared with that of glycyrrhetinic acid (2), the aglycone of glycyrrhizin from licorice. Compound 1, when administered to rats intraperitoneally at a dose of 600 mg/kg, inhibited homologous passive cutaneous anaphylaxis more strongly than 2 at the same dose. Compound 1 also significantly inhibited delayed hypersensitivity in mice which could not be inhibited by 2. In contrast to 2, 1 showed not only little toxicity but no visible side effects on mice, without impairing the activity of the hepatic enzyme (4,5 beta-dihydrocortisone:NADP+ delta 4-oxidoreductase) involved in steroid catabolism. 相似文献
27.
Liver histopathology in clinical Reye syndrome 总被引:1,自引:0,他引:1
Analysis of the liver histopathology in 19 children with clinical Reye syndrome (RS) revealed that nine had diffuse panlobular steatosis, one giant cell hepatitis, one a mild choledochal cyst with inflammation, two multifocal spotty necrosis and one multiple centrilobular necrosis, the other five being normal. Four of the nine patients with diffuse panlobular steatosis showed microvesicular fatty droplets with central nuclei, which was consistent with findings characteristic for typical RS. Two cases showed a periportal area dominant macrovesicular fatty change, which was highly suggestive for metabolic disorder. In the other three cases, the findings were so variable in terms of the size of lipid droplets and the location of nuclei in hepatocytes that it was not possible to provide any clue for defining a diagnosis. These results confirmed the legitimacy of the diagnostic criteria of RS which included a liver biopsy as one of the mandatory conditions. They also indicated that RS-mimicking clinical pictures can be presented by miscellaneous conditions in which liver histology does not necessarily helpful in establishing definite diagnosis. 相似文献
28.
T Tanaka 《Kekkaku : [Tuberculosis]》1989,64(5):351-360
A genomic library of Mycobacterium tuberculosis strain Aoyama B in Escherichia coli K-12 was constructed by cloning Sau 3A I cleaved M. tuberculosis Aoyama B chromosomal DNA into pUC18, pUC181 or pUC182. Clones reacting with anti-PPDs-rabbit-serum were screened by immunoblotting among 3 x 10(4) clones. Seven clones were selected; designating pAT 01, pAT 101, pAT 102, pAT 103, pAT 104, pAT 105 and pAT 201. On Western blotting, they were shown to produce 15 kD (pAT 01, pAT 101, pAT 105), 18 kD (pAT 103) and 60 kD (pAT 102, pAT 201) peptide antigens. Restriction endonuclease map of each of the above clones was composed, and putative coding frames of anti-PPDs-rabbit-serum reactive peptides were deduced by analysing deletion derivatives. Nucleotide sequence of pAT 01, encoding for 15 kD peptide antigen was analyzed, and a Hinf I-Hinf I fragment in pAT 01 was subcloned into pUC 18 lambda CPL 1 to determine the direction of its reading frame. The origin of promoter that drives cloned mycobacterial genes in E. coli was discussed. 相似文献
29.
Tatsurou Tanaka Yasuhiro Morimoto Hiroshi Takano Kazuhiro Tominaga Shinji Kito Sachiko Okabe Tetsu Takahashi Jin-ichi Fukuda Takeshi Ohba 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2005,100(5):609-613
OBJECTIVE: To evaluate a proposed technique for the 3-dimensional (3D) detection of hemangiomas, including vascular malformation and their feeding arteries, in the head and neck. The new technique combines phase-contrast magnetic resonance angiography (PCMRA) without contrast medium and 3D fast asymmetric spin-echo (FASE) sequences. METHODS: The technique was applied to 3 patients having hemangiomas in the head and neck region. In 1 patient the image obtained with the proposed technique was compared to that obtained by standard contrast angiography. RESULTS: In all 3 patients, the 3D presence of the hemangiomas and the feeding arteries were well defined in images created by the proposed technique. Additionally, the characterization of the hemangioma's 3D structure and distribution of the feeding arteries coincided with those observed using contrast angiography in the case for which contrast angiography was also performed. CONCLUSIONS: Preliminary experience shows that the proposed technique combining 3D-FASE and 3D-PCMRA is useful to visualize both the 3D structure of hemangiomas and to identify the 3D distribution of the feeding arteries without using contrast medium. 相似文献
30.
Makoto Osawa Yutaka Ito Toyohiro Hirai Rie Isozumi Shunji Takakura Yasuhiro Fujimoto Yoshitsugu Iinuma Satoshi Ichiyama Koichi Tanaka Michiaki Mishima 《Liver transplantation》2007,13(4):566-570
Invasive aspergillosis (IA) is a severe complication of liver transplantation. Risk factors for IA after deceased donor liver transplantation (DDLT) have been presented in several reports, but are not well established for living donor liver transplant recipients. Here, a retrospective case-control study was performed. Five cases with IA were investigated after living donor liver transplantation (LDLT) between January 1999 and December 2002 at Kyoto University Hospital. For comparison, living donor liver transplant recipients without IA were taken as controls. These patients had undergone LDLT 1 month before or after each IA case and had the same survival times as the latter. We evaluated the clinical and laboratory findings for both groups up until their demise. Patients with IA after LDLT had a very poor prognosis. By univariate analysis, risk factors for IA were preoperative intensive care unit stay (P = 0.02) and preoperative steroid administration (P = 0.02). Preoperative steroid administration for fulminant hepatitis possibly predisposed to the development of IA after LDLT. 相似文献