全文获取类型
收费全文 | 8707篇 |
免费 | 545篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 81篇 |
儿科学 | 215篇 |
妇产科学 | 166篇 |
基础医学 | 1348篇 |
口腔科学 | 248篇 |
临床医学 | 632篇 |
内科学 | 2253篇 |
皮肤病学 | 349篇 |
神经病学 | 759篇 |
特种医学 | 193篇 |
外科学 | 866篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 330篇 |
眼科学 | 264篇 |
药学 | 662篇 |
中国医学 | 35篇 |
肿瘤学 | 875篇 |
出版年
2023年 | 59篇 |
2022年 | 131篇 |
2021年 | 219篇 |
2020年 | 115篇 |
2019年 | 227篇 |
2018年 | 226篇 |
2017年 | 177篇 |
2016年 | 227篇 |
2015年 | 223篇 |
2014年 | 302篇 |
2013年 | 358篇 |
2012年 | 586篇 |
2011年 | 631篇 |
2010年 | 362篇 |
2009年 | 308篇 |
2008年 | 512篇 |
2007年 | 585篇 |
2006年 | 574篇 |
2005年 | 570篇 |
2004年 | 534篇 |
2003年 | 476篇 |
2002年 | 476篇 |
2001年 | 146篇 |
2000年 | 100篇 |
1999年 | 137篇 |
1998年 | 108篇 |
1997年 | 84篇 |
1996年 | 64篇 |
1995年 | 44篇 |
1994年 | 53篇 |
1993年 | 41篇 |
1992年 | 66篇 |
1991年 | 51篇 |
1990年 | 64篇 |
1989年 | 58篇 |
1988年 | 49篇 |
1987年 | 39篇 |
1986年 | 32篇 |
1985年 | 34篇 |
1984年 | 28篇 |
1983年 | 25篇 |
1982年 | 14篇 |
1980年 | 13篇 |
1979年 | 19篇 |
1978年 | 18篇 |
1974年 | 13篇 |
1972年 | 12篇 |
1971年 | 12篇 |
1969年 | 12篇 |
1967年 | 14篇 |
排序方式: 共有9315条查询结果,搜索用时 15 毫秒
21.
22.
Toshihiro Seo Taketoshi Kajihara Toshiro Iijima 《Macromolecular chemistry and physics.》1987,188(6):1295-1304
The catalytic hydrolysis of phenyl esters in systems containing ß-cyclodextrin (ß-CD) and polyelectrolytes was investigated. Poly(methacrylic acid) was found to exhibit an inhibition effect on the hydrolysis, while poly(sodium styrenesulfonate) (NaPSS) shows a pronounced acceleration effect on the hydrolysis: the larger the molecular weight and the lower the degree of substitution, the greater is the acceleration effect. On the other hand, sodium ethylbenzenesulfonate and sodium dodecylbenzenesulfonate inhibit the reaction. The acceleration of the reaction in presence of NaPSS is attributed to the concentration of ß-CD and the substrate esters near to the chain of the macromolecule, through inclusion effects and hydrophobic interactions. 相似文献
23.
24.
25.
26.
27.
Takuya Watanabe Keiko Takahashi Tomoko Kanome Shigeki Hongo Akira Miyazaki Shinji Koba Takashi Katagiri Rajbabu Pakara Claude R Benedict 《Hypertension research》2006,29(10):821-831
Human urotensin-II (U-II) is the most potent vasoactive peptide identified to date, and may be involved in hypertension and atherosclerosis. We investigated the effects of the interactions between U-II or other vasoactive agents and mildly oxidized low-density lipoprotein (mox-LDL) or hydrogen peroxide (H2O2) on the induction of vascular smooth muscle cell (VSMC) proliferation. Growth-arrested rabbit VSMCs were incubated with vasoactive agents (U-II, endothelin-1, angiotensin-II, serotonin, or thromboxane-A2) in the presence or absence of mox-LDL or H2O2. [3H]Thymidine incorporation into DNA was measured as an index of VSMC proliferation. On interaction with mox-LDL or H2O2, U-II induced the greatest increase in [3H]thymidine incorporation among these vasoactive agents. A low concentration of U-II (10 nmol/l) enhanced the potential mitogenic effect of low concentrations of mox-LDL (120 to 337%) and H2O2 (177 to 226%). U-II at 50 nmol/l showed the maximal mitogenic effect (161%), which was abolished by G protein inactivator (GDP-beta-S), c-Src tyrosine kinase inhibitor (radicicol), protein kinase C (PKC) inhibitor (Ro31-8220), extracellular signal-regulated kinase (ERK) kinase inhibitor (PD98059), or Rho kinase inhibitor (Y27632). Mox-LDL at 5 microg/ml showed the maximal mitogenic effect (211%), which was inhibited by free radical scavenger (catalase), intracellular and extracellular antioxidants (N-acetylcysteine and probucol), nicotinamide adenine dinucleotide phosphate oxidase inhibitor (diphenylene iodonium), or c-Jun N-terminal kinase (JNK) inhibitor (SP600125). These results suggested that U-II acts in synergy with mox-LDL in inducing VSMC DNA synthesis at the highest rate among these vasoactive agents. Activation of the G protein/c-Src/PKC/ERK and Rho kinase pathways by U-II together with the redox-sensitive JNK pathway by mox-LDL may explain the synergistic interaction between these agents. 相似文献
28.
Changes of amplitude and implicit time of human cone electroretinogram (ERG) were studied during dark adaptation and succeeding light adaptation. Dark-adapted cone ERG was isolated by subtracting scotopic blue response from matched scotopic red response. The former represented the rod-mediated b-wave, while the latter consisted of both rod-mediated b-wave and cone-mediated b-wave or x-wave. The b-wave amplitude of dark-adapted cone ERG remained unchanged during dark adaptation, while the implicit time increased systematically, reaching a plateau. Light-adapted cone ERG was obtained by red stimulus lights under a bright background light. The amplitude of light-adapted cone ERG was markedly suppressed through dark adaptation but it recovered gradually during light adaptation, reaching the base line level. The implicit time was unchanged during light adaptation. 相似文献
29.
Shiro Nakaike Takehiro Yamagishi Kazunori Samata Keiko Nishida Kouko Inazuki Tomoko Ichihara Yoshihiro Migita Susumu Otomo Hironaka Aihara Shigeru Tsukagoshi 《Cancer chemotherapy and pharmacology》1989,23(3):135-139
Summary A novel antitumor compound, N--dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]-phenazine-6-carboxamide sodium salt (NC-190) was evaluated for its antitumor activity in experimental murine tumor systems. In the initial studies with P388 leukemia (i.p.-i.p.), NC-190 led to an increase of >200% in life span (ILS), and 75% of the mice were alive on day 30, when the optimal dose (50 mg/kg, days 1–5) was given. Additionally, the compound had significant activities against i.p. inoculated mouse L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma, sarcoma 180, mouse hepatoma MH134, and rat Yoshida sarcoma and Yoshida ascites hepatoma AH130. The optimal dose resulted in a >280% ILS with a 30-day survival of 50% in mice with L1210 leukemia (100 mg/kg, days 1–5), a 156% ILS in mice with B16 melanoma (50 mg/kg, days 1–5), a 98% ILS with a 90-day survival of 25% in mice with M5076 reticulum cell sarcoma (25 mg/kg, days 1, 5, 9, and 13), a >300% ILS with a 60-day survival of 50% in mice with sarcoma 180 (50 mg/kg, days 3–10), a 148% ILS with a 60-day survival of 25% in mice with MH134 (25 mg/kg, days 1–5), a 129% ILS with a 60-day survival of 12.5% in rats with Yoshida sarcoma (12.5 mg/kg, day 3–10), and a >161% ILS with a 60-day survival of 50% in rats with AH130 (6.3 mg/kg, days 3–10). In the experiments with s.c. inoculated tumors, NC-190 not only inhibited tumor growth, but also increased the life span of mice with Lewis lung carcinoma or B16 melanoma. The 60-day survivors accounted for 60% and 30% in mice with Lewis lung carcinoma and B16 melanoma, respectively. The compound significantly inhibited the spontaneous lung metastasis of Lewis lung carcinoma by more than 90% when eight daily i.v. injections were given. NC-190 was active by the i.p., s.c., and i.v. routes. Five consecutive daily i.p. doses (days 1–5) were more effective than a single dose (day 1), two doses (days 1 and 5), or three doses (days 1, 5, and 9). NC-190 warrants further study as a potential antineoplastic agent against human neoplasms, as it has a broad spectrum of antitumor activity and inhibits metastasis.Abbreviations
ILS
increase in life span
-
MST
median survival time
-
MMC
mitomycin C
-
ADM
adriamycin
-
CPA
cyclophosphamide
-
5-FU
5-fluorouracil 相似文献
30.
Tomoko Yoshinari Yoshikazu Iwasawa Keiko Miura Ikuko S. Takahashi Takahiro Fukuroda Kunio Suzuki Akira Okura 《Cancer chemotherapy and pharmacology》1989,24(6):367-370
Summary BS compounds, a series of new dihydropyridines, successfully overcame multidrug resistance in P388/ADR cells in vitro. These agents synergistically potentiated the cytotoxicity of Adriamycin to P388/ADR cells at a concentration of 1–2 M, whereas they showed hardly any synergistic effect in the parental cell line (P388/S) at the same concentration. They inhibited the active drug efflux in P388/ADR cells as well as the binding of [G-3H]-vinblastine to membrane vesicles from P388/ADR, which was increased in resistant P388 cells as compared with parental cells. Besides, unlike the activity of clinically used calcium antagonists, the calcium antagonistic activity associated with BS compounds was very weak: their arterial relaxation activity was <21% of that of verapamil. These data suggest that BS compounds specifically overcome multidrug resistance without the serious hypotensive side effects that accompany the use of verapamil orother calcium antagonists. 相似文献