全文获取类型
收费全文 | 6601篇 |
免费 | 318篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 106篇 |
妇产科学 | 75篇 |
基础医学 | 854篇 |
口腔科学 | 166篇 |
临床医学 | 372篇 |
内科学 | 1680篇 |
皮肤病学 | 60篇 |
神经病学 | 440篇 |
特种医学 | 324篇 |
外科学 | 1100篇 |
综合类 | 52篇 |
预防医学 | 194篇 |
眼科学 | 204篇 |
药学 | 524篇 |
中国医学 | 14篇 |
肿瘤学 | 773篇 |
出版年
2023年 | 33篇 |
2022年 | 59篇 |
2021年 | 144篇 |
2020年 | 72篇 |
2019年 | 108篇 |
2018年 | 120篇 |
2017年 | 107篇 |
2016年 | 138篇 |
2015年 | 145篇 |
2014年 | 189篇 |
2013年 | 246篇 |
2012年 | 384篇 |
2011年 | 419篇 |
2010年 | 190篇 |
2009年 | 172篇 |
2008年 | 342篇 |
2007年 | 395篇 |
2006年 | 331篇 |
2005年 | 365篇 |
2004年 | 373篇 |
2003年 | 349篇 |
2002年 | 358篇 |
2001年 | 138篇 |
2000年 | 124篇 |
1999年 | 149篇 |
1998年 | 86篇 |
1997年 | 103篇 |
1996年 | 66篇 |
1995年 | 69篇 |
1994年 | 70篇 |
1993年 | 72篇 |
1992年 | 101篇 |
1991年 | 104篇 |
1990年 | 83篇 |
1989年 | 74篇 |
1988年 | 63篇 |
1987年 | 55篇 |
1986年 | 72篇 |
1985年 | 75篇 |
1984年 | 46篇 |
1983年 | 47篇 |
1982年 | 30篇 |
1981年 | 27篇 |
1980年 | 20篇 |
1979年 | 25篇 |
1978年 | 27篇 |
1977年 | 22篇 |
1976年 | 20篇 |
1974年 | 26篇 |
1968年 | 18篇 |
排序方式: 共有6969条查询结果,搜索用时 31 毫秒
1.
2.
Masahiro Yamauchi Hiroko Kusano Etsuko Saito Takeshi Iwata Masashi Nakakura Yasuki Kato Takaaki Uochi Shiro Akinaga Noboru Aoki 《Journal of controlled release》2006,114(2):268-275
Previously, we demonstrated that wrapping dextran fluorescein anionic/cationic lipid complexes with neutral lipids produced a stable formulation that markedly increased the duration of the compound in plasma after intravenous administration to rats. The improved drug-delivery properties of the wrapped liposomes (WL) relative to other formulations suggested that this technology could offer important advantages for the administration of other polyanionic drugs, including antisense oligodeoxynucleotides (ODN). In the present study, we investigated the value of WL for formulating fluorescence-labeled phosphorothioated ODN (F-ODN). WL encapsulating F-ODN/cationic lipid complexes were prepared efficiently using similar methodology to that used in our earlier study. Studies confirmed that these WL were stable in vitro. Following intravenous administration to mice, free F-ODN and naked F-ODN/cationic lipid complexes were rapidly eliminated whereas administration of the WL resulted in high blood concentrations of drug that were maintained for several hours. Additional studies were conducted in mice that were inoculated with tumor cells (Caki-1 xenograft model, human kidney); in these experiments, intravenous administration of WL delivered 13 times more F-ODN to the tumor site than achieved after injection of free F-ODN. 相似文献
3.
Kengo Maeda Shinji Kume Yoshihiko Nishio Shiro Maeda Yasuhiro Nishida Mikio Suzuki Takahiro Nakaguchi Toru Kawabata Osamu Hashimoto Takashi Hisanaga Atsunori Kashiwagi Hitoshi Yasuda 《Clinical neurology》2006,46(4):266-269
We report a 53-year-old woman with severe Graves' ophthalmopathy accompanied by uncontrolled myasthenia gravis. She presented remarkable exophthalmos, chemosis, and restriction of eye movement. Despite plasma exchange, steroid pulse therapy, local injection of steroid, and irradiation, ocular symptoms did not ameliorate. Since optic neuropathy was seen, orbital decompression surgery was performed in the left eye. Bilateral chemosis was improved after the surgery. Five years after surgery, there was no ocular palsy in the operated left eye, but in the contralateral eye. For the good prognosis of the eye movement, orbital decompression might be recommended in the severe Graves' ophthalmopathy accompanied by the optic neuropathy and/or ophthalmoplegia with proptosis. 相似文献
4.
Shiro Akinaga Tadashi Ashizawa Katsushige Gomi Hiroe Ohno Makoto Morimoto Chikara Murakata Masami Okabe 《Cancer chemotherapy and pharmacology》1992,29(4):266-272
Summary Novel derivatives of K-252a, (8R*,9S*,11S*)-(–)-9-hydroxy-9-methoxycarbonyl-8-methyl-2,3,9,10-tetrahydro-8, 11-epoxy-1H,8H,11H-2,7b,11a-triazadibenzo [a,g]-cycloocta[cde]trinden-1-one, an inhibitor of protein kinases and calmodulin-dependent phosphodiesterase, were synthesized and evaluated for their antitumor activity in vitro and in vivo. Of ten derivatives tested, four were active against the P388 murine leukemia i. p.-i. p. system, although K-252a was inactive. Among these derivatives, KT6124 was selected for further biological evaluation studies because its efficacy was the highest. KT6124 was also active against sarcoma 180 and B16 melanoma. It exerted a relatively broad spectrum of antiproliferative activity against 20 human tumor cell lines in vitro. To determine the mechanism(s) of action underlying the antitumor activity of KT6124, we tested the drug for inhibition of protein kinases, including Ca2+-and phospholipid-dependent protein kinase (PKC), in intact A431 human epidermoid carcinoma cells in comparison with the PKC-inhibitory activity of K-252a. KT6124 did not antagonize the action of phorbol 12-myristate 13-acetate (PMA) in A431 cells, whereas K-252a did, suggesting that KT6124 may not act on protein kinases in the cells. The interaction of KT6124 with DNA in living cells was examined by the alkaline elution method. KT6124 apparantly exhibited DNA scission both dose-and time-dependently in the target cells. The DNA breakage was dependent on proteinase K treatment, suggesting its possible interaction with DNA-related enzyme(s). These results indicate that KT6124 exerts antitumor activity by acting on DNA or on DNA-related enzyme(s) in tumor cells rather than via the inhibition of protein kinases. 相似文献
5.
Masao Amari Katsuji Taguchi Minoru Iwahara K Shibuya Shiro Naoe 《Medical Electron Microscopy》2002,35(4):225-233
To elucidate the effect of fibroblast growth factor on the phenotypical conversion of fibroblasts to mesothelial cells, both immunohistochemical and ultrastructural examinations were carried out on cultured spheroids that were composed of fibroblasts obtained from the parietal pleura of rats with and without addition of antifibroblast growth factor receptor antibody. In the present study, antifibroblast growth factor receptor antibody was employed to block the effect of the autocrine component of fibroblast growth factor in the culture medium. Phenotypical conversion from fibroblast to mesothelial cells was clearly blocked in the experimental group, to which culture medium had been added with antifibroblast growth factor receptor antibody, whereas the control group, cultured without addition of antifibroblast growth factor receptor antibody, showed phenotypical conversion of fibroblasts that was confirmed by the development of macula adherens, microvilli, and positive expression of cytokeratin. These results indicate the possibility that fibroblast growth factor plays a key role in the process of phenotypic conversion of fibroblasts to regenerated mesothelial cells. 相似文献
6.
7.
Oswens Siu Hung Lo Wai Lun Law Hok Kwok Choi Yee Man Lee Judy Wai Chu Ho Chi Leung Seto 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2007,392(2):173-178
OBJECTIVES: The study aimed to review the etiologies of patients who underwent surgery for small bowel obstruction (SBO) and to evaluate the risk factors affecting the early postoperative outcomes. MATERIALS AND METHODS: A case series of 430 patients (252 men) with a mean age of 64.5 years, who underwent 437 operations for SBO, were retrospectively reviewed. RESULTS: Peritoneal adhesions and hernia were the most common causes of SBO, contributing 42.3 and 26.8% of all cases, respectively. Strangulation occurred in 27.7% and caused nonviable bowel in 13.0% of obstructing episodes. Old age (age >/= 70 years), female patient, nonadhesive obstruction, and hernia were the independent significant factors associated with bowel strangulation. The 30-day mortality was 6.5%, and the median postoperative hospital stay was 8 days. Old age, the presence of premorbid pulmonary disease, and malignant obstruction were the independent factors associated with operative mortality. The overall complication rate was 35.5%, and old age was the only significant factor associated with postoperative complications. CONCLUSIONS: Surgery for SBO is still associated with significant mortality and morbidity. As old age is significantly associated with an increased incidence of strangulation, operative mortality, and complications, this group of patients should be managed with extra cautions to avoid unfavorable outcome of surgery. 相似文献
8.
This paper describes a new class of reaction, group-transfer alternating copolymerization (GTAC), between 2-phenyl-1,3,2-dioxaphosphorinane ( 1 ) and trimethylsilyl 2-(acryloyloxy)ethanesulfonate ( 2 ). The copolymerization took place without any added catalyst and proceeded via quantitative trimethylsilyl group-transfer process to give a 1:1 alternating copolymer 3a having a ketene silyl acetal group in the main chain. Results of spectroscopy as well as alkaline hydrolysis and bromination of the copolymer confirmed the structure. 相似文献
9.
T Nishiyama A Hirasaki Y Odaka K Seto I Goto 《Masui. The Japanese journal of anesthesiology》1990,39(2):230-236
We compared midazolam 0.2 mg.kg-1 and fentanyl 50 micrograms with thiamylal 4 mg.kg-1 for rapid sequence induction. We could use midazolam safely in patients with bronchial asthma or drug allergy. There was no difference in time from the beginning of induction to intubation between midazolam treated group and thiamylal treated group. Changes in systolic as well as diastolic blood pressure and heart rate during 2 hours from intubation were smaller in midazolam treated group than in thiamylal treated group. In midazolam treated group, no arrhythmias were observed at the time of intubation. We could reduce the amount of anesthetics in midazolam treated group during 2 hours from intubation. From the results mentioned above, we conclude that midazolam is a useful agent for rapid sequence induction. 相似文献
10.
The effect of dietary manipulation on global tooth uptake of 47Ca-chloride was evaluated in three rat models of metabolic bone diseases verified by histologic bone study. The 24-hr tooth uptake of 47Ca-chloride was significantly decreased in the osteomalacic group, and was increased in the osteoporotic group at the fourth week. Tooth uptake closely paralleled femoral uptake at a correlation coefficient of 0.73 (p less than 0.01). The uptake of 47Ca-chloride in tooth was found to be more affected by dietary manipulation than that in femur in our rat models. 相似文献