全文获取类型
收费全文 | 56807篇 |
免费 | 3324篇 |
国内免费 | 663篇 |
专业分类
耳鼻咽喉 | 987篇 |
儿科学 | 684篇 |
妇产科学 | 835篇 |
基础医学 | 9815篇 |
口腔科学 | 1388篇 |
临床医学 | 5019篇 |
内科学 | 10750篇 |
皮肤病学 | 1892篇 |
神经病学 | 3986篇 |
特种医学 | 3210篇 |
外科学 | 7512篇 |
综合类 | 242篇 |
现状与发展 | 1篇 |
一般理论 | 17篇 |
预防医学 | 2733篇 |
眼科学 | 1244篇 |
药学 | 5018篇 |
中国医学 | 624篇 |
肿瘤学 | 4837篇 |
出版年
2023年 | 428篇 |
2022年 | 1327篇 |
2021年 | 2062篇 |
2020年 | 987篇 |
2019年 | 1290篇 |
2018年 | 1668篇 |
2017年 | 1245篇 |
2016年 | 1762篇 |
2015年 | 2573篇 |
2014年 | 3070篇 |
2013年 | 3507篇 |
2012年 | 5321篇 |
2011年 | 4812篇 |
2010年 | 2829篇 |
2009年 | 2397篇 |
2008年 | 3427篇 |
2007年 | 3147篇 |
2006年 | 2672篇 |
2005年 | 2368篇 |
2004年 | 2032篇 |
2003年 | 1698篇 |
2002年 | 1446篇 |
2001年 | 1376篇 |
2000年 | 1272篇 |
1999年 | 919篇 |
1998年 | 422篇 |
1997年 | 318篇 |
1996年 | 278篇 |
1995年 | 235篇 |
1994年 | 189篇 |
1993年 | 180篇 |
1992年 | 340篇 |
1991年 | 330篇 |
1990年 | 293篇 |
1989年 | 296篇 |
1988年 | 269篇 |
1987年 | 284篇 |
1986年 | 189篇 |
1985年 | 189篇 |
1984年 | 133篇 |
1983年 | 134篇 |
1982年 | 74篇 |
1981年 | 75篇 |
1980年 | 61篇 |
1979年 | 82篇 |
1978年 | 73篇 |
1975年 | 56篇 |
1974年 | 60篇 |
1973年 | 51篇 |
1972年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
Poly(L-lysine)-g-poly(D,L-lactic-co-glycolic acid) micelles for low cytotoxic biodegradable gene delivery carriers. 总被引:3,自引:0,他引:3
Poly(lactic-co-glycolic acid) (PLGA)-grafted poly(L-lysine) (PLL) (PLL-g-PLGA) was synthesized to demonstrate its micelle-forming property in an aqueous solution. The micelles were used as a gene delivery carrier. The hydrodynamic diameter of PLL-g-PLGA micelles in an aqueous solution was ca. 149 nm with a narrow size distribution. Critical micelle concentration (cmc) was 9.6 mg/l. The PLL-g-PLGA micelles could be used to produce compact nanoparticulate complexes with plasmid DNA, which could efficiently protect the complexed DNA from enzymatic degradation by DNase I. The micelle/DNA complexes had highly compacted structure sized between 200-300 nm with a positive surface charge value. The PLL-g-PLGA micelles exhibited much higher transfection efficiency with lower cytotoxicity than PLL. Here, we demonstrated that biodegradable and cationic PLL-g-PLGA micelles could be used as an effective DNA condensation carrier for gene delivery system. 相似文献
122.
123.
Ceftriaxone-associated gallbladder sludge. Identification of calcium-ceftriaxone salt as a major component of gallbladder precipitate 总被引:5,自引:0,他引:5
Ceftriaxone, a third-generation cephalosporin, is partially excreted into bile. With its clinical use, the formation of gallbladder sludge detected by ultrasonography has been reported. Four surgical specimens were examined and no gallstones were found. Instead, fine precipitates of 20-250 microns were present. Microscopically, there was a small number of cholesterol monohydrate crystals and bilirubin granules among an abundant amount of granular-crystalline material that was not morphologically cholesterol monohydrate crystals. The chemical composition of the precipitates (n = 4) was determined. There was a small amount of cholesterol (1.7% +/- 0.8%) and bilirubin (13.9% +/- 0.74%). The major component of the precipitate was a residue. On further analysis using thin-layer chromatography, high-performance liquid chromatography, and electron microprobe analysis, the residue was identified as a calcium salt of ceftriaxone. The residue also had identical crystal morphology and chromatographic elution profile as authentic calcium-ceftriaxone standards. It is concluded that ceftriaxone, after excretion and being concentrated in the gallbladder bile, can form a precipitate. The major constituent has been identified as a ceftriaxone-calcium salt. 相似文献
124.
125.
126.
Doxorubicin-conjugated biodegradable polymeric micelles having acid-cleavable linkages. 总被引:13,自引:0,他引:13
Doxorubicin was chemically conjugated to the terminal end of a di-block copolymer composed of poly(L-lactic acid) (PLLA) and methoxy-poly(ethylene glycol) (mPEG) via two acid-cleavable linkages. A hydrazone bond and a cis-acotinyl bond were formed between doxorubicin and the terminal group of PLLA segment in the block copolymer. Doxorubicin-conjugated PLLA-mPEG di-block copolymers self-assembled to form micelles in aqueous solution. The doxorubicin-conjugated micelles were about 89.1 nm in diameter and their critical micelle concentration was 1.3 microg/ml. These values were comparable with those of unconjugated micelles. In an acidic condition, the conjugated doxorubicin in the hydrazone linkage was readily cleaved, releasing doxorubicin in an intact structure. Doxorubicin-conjugated PLLA-mPEG micelles were more potent in cell cytotoxicity than free doxorubicin, suggesting that they were more easily taken up within cells with concomitant rapid release of cleaved doxorubicin into the cytoplasm from acidic endosomes. 相似文献
127.
J D Lee K H Shin S N Cho J S Shin M G Lee W I Yang C Y Park H S Yoo J T Lee O D Awh 《European journal of nuclear medicine》1992,19(12):1011-1015
Immunoscintigraphy with radiolabelled monoclonal antibodies is widely used to detect solid tumours, but only a few trials have been carried out concerning the specific in vivo localization of an inflammatory process. The purpose of this study was to investigate the detectability of tuberculous foci utilizing this method with radiolabelled bacillus Calmette-Guérin (BCG)-specific F(ab')2 in rabbits. All of the tuberculous lesions (n = 8) were clearly visualized on serial scintigraphy for up to 48 h after injection of the antibody. Immunohistochemical and Ziel-Neelson staining of the tuberculous lesions confirmed the presence of the tuberculous antigens and bacilli. It failed to demonstrate any sustained retention of the BCG-specific antibody fragment in the control group with syphilitic orchitis (n = 2). Therefore, the specific in vivo localization of tuberculosis is feasible by immunoscintigraphy. 相似文献
128.
H D Lee C O Suh W H Jung K K Oh H B Park H S Chi B R Kim J S Min 《Yonsei medical journal》1992,33(3):272-276
This is the first preliminary report among two consecutive papers. Partial mastectomy(PM), axillary lymph node dissection(AD) and radiotherapy (RT) were performed on seventeen operable breast cancer patients who had been admitted from April 1991 to March 1992 to the department of surgery, Yongdong Severance Hospital for improved cosmetic appearance and better survival rate. Of seventeen patients, 47% were T1 lesion and 76% were stage I and II. Extensive intraductal component(EIC) within or around the tumor was also analyzed. Twenty nine per cent of the patients were EIC positive. The mean number of axillary lymph nodes was 21.5 after PM with AD and 20.5 after mastectomy. For radiotherapy, 4,500 rad was delivered to the breast parenchyma and 1,600 rad of boost to the primary tumor site using the electron beam method after surgery. All patients have since been living well without any local recurrence and were satisfied with breast preservation for the one-year follow-up period. We concluded that the PM, AD and RT can be another surgical treatment modality of breast cancer. A longer follow-up data will be followed on the second paper. 相似文献
129.
T Oka A Okuyama H Fujisue H Itatani Y C Park A Wakabayashi M Takada T Uemura K Kori N Kanbara 《Hinyokika kiyo. Acta urologica Japonica》1987,33(8):1157-1161
At Kanbara Hospital, 187 patients with urolithiasis have been treated by extracorporeal shock-wave lithotripsy (ESWL) since the first ESWL treatment in December, 1986. Some cases in which ESWL could not be performed easily were experienced. These difficulties were analyzed retrospectively and some problems in the ESWL treatment are discussed. 相似文献
130.
Byung Hoon Han Myung Hwan Park Yong Nam Han Lin Keun Woo 《Archives of pharmacal research》1986,9(1):21-23
Over twelve alkaloids were delected in the roots ofPanax ginseng C.A. Meyer. Among them three alkaloids were isolated and were identified as N9-formylharman, ethyl β-carboline-1-carboxylate and perlolyrine on the basis of spectroscopic studies. 相似文献