全文获取类型
收费全文 | 5873篇 |
免费 | 284篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 113篇 |
妇产科学 | 107篇 |
基础医学 | 564篇 |
口腔科学 | 133篇 |
临床医学 | 365篇 |
内科学 | 1525篇 |
皮肤病学 | 147篇 |
神经病学 | 437篇 |
特种医学 | 194篇 |
外科学 | 1054篇 |
综合类 | 19篇 |
一般理论 | 1篇 |
预防医学 | 136篇 |
眼科学 | 99篇 |
药学 | 271篇 |
中国医学 | 13篇 |
肿瘤学 | 981篇 |
出版年
2023年 | 38篇 |
2022年 | 54篇 |
2021年 | 131篇 |
2020年 | 87篇 |
2019年 | 101篇 |
2018年 | 148篇 |
2017年 | 129篇 |
2016年 | 146篇 |
2015年 | 136篇 |
2014年 | 176篇 |
2013年 | 206篇 |
2012年 | 378篇 |
2011年 | 405篇 |
2010年 | 246篇 |
2009年 | 239篇 |
2008年 | 356篇 |
2007年 | 410篇 |
2006年 | 370篇 |
2005年 | 373篇 |
2004年 | 382篇 |
2003年 | 334篇 |
2002年 | 370篇 |
2001年 | 89篇 |
2000年 | 85篇 |
1999年 | 64篇 |
1998年 | 67篇 |
1997年 | 57篇 |
1996年 | 57篇 |
1995年 | 40篇 |
1994年 | 29篇 |
1993年 | 32篇 |
1992年 | 51篇 |
1991年 | 29篇 |
1990年 | 41篇 |
1989年 | 40篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 25篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 17篇 |
1979年 | 23篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1971年 | 13篇 |
1968年 | 7篇 |
排序方式: 共有6197条查询结果,搜索用时 46 毫秒
61.
It has been shown previously that soluble material extracted from Pasteurella multocida P-1059 by a 2.5% NaCl solution protects turkeys from generalized septicemia at a subsequent challenge exposure to the organism. In the present study, a protective antigen was purified from the crude soluble material by chromatographic methods. Four protein peaks were obtained by gel filtration with Sephadex G-200. The protective antigen was detected only in the first peak fraction, which contained a substantial amount of carbohydrate. The peak 1 fraction was adsorbed onto DEAE-cellulose and eluted by a linear gradient of NaCl. Fractions corresponding to a single protein peak were pooled and passed through an immunoadsorbent column to remove any possible serum component originating from the growth medium. The purified antigen had a carbohydrate/protein ratio of 1.5 and formed a single precipitin line with rabbit antiserum against the crude material in gel diffusion and immunoelectrophoresis analyses. The antigen produced antibodies in rabbits and turkeys which formed a single precipitin line against the crude material. Upon sodium dodecyl sulfate-polyacryl-amide gel electrophoresis, the purified antigen showed three protein bands, corresponding to molecular weights of 44,000, 31,000, and 25,000, and one carbohydrate band. The carbohydrate band did not correspond to any of the three protein bands. Upon isoelectric focusing gel analysis, the purified antigen showed two bands (pI = 3.5 to 4.0 and 4.5 to 5.5), but the two bands were antigenically identical by isoelectric focusing crossed immunoelectrophoresis. The 50% protective dose of the purified antigen was between 10 and 50 μg of protein in trials where two doses were given at 14-day intervals to 10- to 20-week-old turkeys. 相似文献
62.
Hirokazu Tsukahara Masahiro Hiraoka Masanori Kurivama Masakazu Saito Kiyoshi Morikawa Mitsuhiko Kuroda Toshiro Tominaga Masakatsu Sudo 《Pediatric nephrology (Berlin, Germany)》1993,7(2):199-201
Urinary 1-microglobulin (U-A1M) was measured in healthy term infants on days 1, 4, 7, 14, 28, 90 and 180 of life. U-A1M was high until day 14 and declined thereafter. It was significantly correlated with urinary 2-microglobulin (U-B2M) throughout the study, but not with serum A1M on days 1 or 7. Similar to U-B2M, U-A1M in the clinically stable term infants with intrauterine growth retardation (n=4–7) was not elevated on days 1–7. In the sick infants who needed immediate resuscitatio at birth (n=4–8), U-A1M as well as U-B2M was high on days 1–7 and then decreased to normal levels, suggesting that U-A1M can be used as a sensitive marker of acute proximal tubular damage and its recovery. These observations indicate that U-A1M is a useful index of proximal tubular function in early infancy. 相似文献
63.
64.
65.
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
66.
O. Suzuki M. Oya A. Kido Y. Katsumata M. Asano 《International journal of legal medicine》1980,86(1):35-39
Summary A simple qualitative method for identification of seminal stains based on a high activity of -glutamyltransferase (-GTP) in human semen is described. It employs the release of -naphthylamine from N--glutamyl--naphthylamide by the -GTP action; -naphthylamine couples with Fast Garnet GBC salt to produce a strong brownish-red color. The data on its simplicity, specificity, and stability show that the present method is suitable for medicolegal examination of seminal stains as a preliminary test. 相似文献
67.
Radiographic Diagnosis of Early Colorectal Cancer, with Special
Reference to the Superficial Type of Invasive Carcinoma 总被引:4,自引:0,他引:4
The possibility of radiographically diagnosing carcinoma with submucosal involvement (invasive carcinoma) is discussed based
on 119 invasive carcinomas of the large bowel that had been treated surgically and colonoscopically over a period of 9 years
(1989—1997) at the Cancer Institute Hospital in Tokyo. Of these lesions, 38 were superficial-type invasive carcinoma, accounting
for 31.9% (38/119) of all invasive colorectal carcinomas, including 36 lesions (94.7%, 36/38) of types IIa and IIa+IIc and
2 lesions (5.3%, 2/38) of type IIc+IIa. No pure type IIc was seen. The radiographic images obtained were correlated with macroscopic
findings and analyzed in terms of visualization of the lesion's contour, central depression, converging folds, and basal indentation.
A definitive diagnosis of superficial invasive carcinoma can be made radiographically if a lesion measures 10 mm and reveals
moderate to severe basal indentation in a complete or nearly complete profile radiographic image. Attention should be paid
to the presence of superficial-type advanced carcinomas measuring 10 mm or less, which is not infrequently experienced in
Japan. Polypoid invasive carcinoma can be definitively diagnosed in the same way with much more certainty than can the superficial
type because few polypoid advanced carcinomas are less than 20 mm. The size and the radiographic sign of the basal indentation
are the most important indicators for the diagnosis of invasive carcinoma.
E-pub: 27 July 2000 相似文献
68.
Yusuke Demizu Kazufumi Kagawa Yasuo Ejima Hideki Nishimura Ryohei Sasaki Toshinori Soejima Toshihiro Yanou Masakazu Shimizu Yoshiya Furusawa Yoshio Hishikawa Kazuro Sugimura 《Radiotherapy and oncology》2004,71(2):207-211
We investigated the biological effect of combining carbon-beam and X-ray in vitro. The results showed that when we employed Gray equivalent as the indication of therapeutic dose, the effects could be explained with simple additive way in the treatment plan. This fact provides important information about the combined therapy of carbon-beam and X-ray. 相似文献
69.
70.
Prognostic significance of clinical and angiogenesis-related factors in low-grade oligodendrogliomas 总被引:4,自引:0,他引:4
BACKGROUND: Keeping in mind that oligodendrogliomas have unpredictable biological behavior, the aim of this study is to investigate the prognostic significance of VEGF expression and microvessel density in a homogeneous series of low-grade oligodendrogliomas. METHODS: For this study 36 patients with a low-grade oligodendroglioma treated by surgical resection and radiotherapy were selected. At the time of surgery, in all cases the Karnofsky Performance Scale (KPS) score was more than 70, and the study of the resected tumor disclosed a Ki-67/MIB-1 labeling index (MBI-1 LI) less than 1%. In this homogeneous series, immunohistochemical studies were performed using monoclonal antibodies against VEGF in order to study the expression of this cytokine, and against vascular endothelial CD-34 antigen, in order to identify microvessels. RESULTS: Our results show that in contrast to low-grade astrocytomas, low-grade oligodendrogliomas lacked immunoreactive VEGF. Oligodendrogliomas with low vascular density (less than 20 microvessels per microscopical field, at 200 x) or high vascular density (more than 100 microvessels per field, at 200 x) were identified, but this factor had no influence on the survival rate of patients. On the other hand, analysis of the present series showed that clinical factors, such as age or extent of surgical resection, were not significantly associated with survival. CONCLUSIONS: In contrast to low-grade astrocytomas, the angiogenesis score of low-grade oligodendrogliomas (counting the number of microvessels in tumor tissue) adds little information to help predict tumor behavior. 相似文献