全文获取类型
收费全文 | 2403篇 |
免费 | 151篇 |
国内免费 | 2篇 |
专业分类
2556篇 |
出版年
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 17篇 |
2019年 | 28篇 |
2018年 | 32篇 |
2017年 | 19篇 |
2016年 | 54篇 |
2015年 | 75篇 |
2014年 | 78篇 |
2013年 | 118篇 |
2012年 | 143篇 |
2011年 | 131篇 |
2010年 | 92篇 |
2009年 | 89篇 |
2008年 | 138篇 |
2007年 | 154篇 |
2006年 | 124篇 |
2005年 | 171篇 |
2004年 | 148篇 |
2003年 | 124篇 |
2002年 | 136篇 |
2001年 | 70篇 |
2000年 | 55篇 |
1999年 | 52篇 |
1998年 | 34篇 |
1997年 | 35篇 |
1996年 | 23篇 |
1995年 | 27篇 |
1994年 | 24篇 |
1993年 | 24篇 |
1992年 | 32篇 |
1991年 | 34篇 |
1990年 | 22篇 |
1989年 | 25篇 |
1988年 | 25篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 17篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1969年 | 3篇 |
1968年 | 4篇 |
排序方式: 共有2556条查询结果,搜索用时 15 毫秒
1.
E T Iwamoto 《Life sciences》1988,43(6):503-508
Intracerebroventricular (i.c.v.) administration of dynorphin A [1-17] induced significant place preference conditioning in male, Sprague-Dawley rats. Place preferences were induced by 2.3 and 3.5 nmole, but not 1.2 nmole of dynorphin A. Co-administration of naloxone, 27.5 nmole but not 5.5 nmole, antagonized the reward response induced by 2.3 nmole of dynorphin A. Leu-enkephalin, 5 or 25 nmole, and dynorphin A [2-17], 2.3 or 3.5 nmole, had no effect in the place conditioning paradigm. 相似文献
2.
Formation of a Tree having a Low Lignin Content 总被引:2,自引:0,他引:2
Received 30 September 2001/ Accepted in revised form 26 October 2001 相似文献
3.
4.
5.
Kenji Masumoto Tomoki Shono Shin-ichiro Takasugi Noboru Hotta Kazutaka Fujishima Yukihide Iwamoto 《Journal of electromyography and kinesiology》2007,17(5):596-604
This study aimed to examine whether walking in water produces age-related differences in muscle activity, stride frequency (SF), and heart rate (HR) response. Surface electromyography (EMG) was used to evaluate muscle activities in six older and six young subjects while they walked in water immersed to the level of the xiphoid process. The trials in water utilized the Flowmill which consists of a treadmill at the base of a water flume. The measurement of maximal voluntary contraction (MVC) of each muscle was made prior to the gait analysis. The %MVCs, which refer to the surface EMG measures, from the gastrocnemius of the older subjects were significantly lower than those of the young subjects, in every experimental condition (P<0.05). In contrast, the %MVCs from the rectus femoris (P<0.05) and the biceps femoris (P<0.001) of older subjects were significantly greater than those of young subjects in every experimental condition. Moreover, the SFs of older subjects were also significantly greater than those of young subjects (P<0.05), while the HR responses of older and young subjects were similar. In conclusion, the older subjects had increased hip musculature activity and decreased ankle plantar flexor activity while walking in water, compared with the young subjects. 相似文献
6.
F Nagase K Ueda K Kawashima S M Jamshedur Rahman K Isobe T Yoshida Y Hasegawa K Ando T Iwamoto E Nagura 《Journal of immunology (Baltimore, Md. : 1950)》1987,138(7):2359-2365
When a murine leukemia L1210-specific Lyt-2+ T cell clone, K7L, was injected i.p. into CD2F1 mice together with L1210, the normal growth of L1210 in the peritoneal cavity of the mice at the early stage (days 0 to 5) was strongly inhibited, but L1210 grew progressively at the middle-stage (days 5 to 10), and then was rejected at the late stage (days 10 to 20). The mice thus survived for long times (more than 60 days), whereas the normal control injected with L1210 alone died within 14 days. The L1210 that grew at the middle stage in mice initially inoculated with L1210 together with K7L was a K7L-insensitive (K7L-) variant. All of eight tumor clones established from L1210-K7L- by limiting dilution was insensitive to the antitumor activity of K7L, and this property of tumor clones was stable after repeated in vitro passage. The initial depression of the L1210 growth by K7L followed by growth and rejection of the variant L1210-K7L- by the host T cell activity was then found to prepare a strong, long-lasting (more than 3 mo) immunity to protect mice against the high-dose (10(7) cells per mouse) challenge of original L1210. Corresponding to this result, definite tumor (L1210)-specific cytotoxic T lymphocyte (CTL) activity against both variant and original L1210 targets was developed by antigen (L1210) restimulation in the culture of spleen cells from these mice, but was not increased to a detectable level before L1210-K7L- variant started to grow. It was suggested that the 1210-K7L- variant and the original L1210 should have the common tumor-specific antigen that was independent of the K7L-reactive antigen, and that original L1210, whose growth was retarded by K7L, primed the host with the common antigen to be enormously boosted by the subsequently growing L1210-K7L- variant. 相似文献
7.
Serum C-peptide responses to glucagon and daily urine C-peptide excretion in successive periods of different treatment in two groups of patients with non-insulin-dependent diabetes mellitus (NIDDM) (mean interval between two tests less than 1 month) were compared. In group A patients (n = 8), the glycemic control was improved after transferring the treatment from sulfonylurea (SU) to insulin (fasting plasma glucose: SU: 192 +/- 47, insulin: 127 +/- 21 mg/dl, mean +/- S.D., p less than 0.01). Fasting serum C-peptide immunoreactivity (CPR) was significantly lower at the period of insulin treatment (SU: 1.93 +/- 1.01, insulin: 1.47 +/- 0.79 ng/ml, p less than 0.05), but there was no difference in the increase in serum CPR (maximal--fasting) (delta serum CPR) during glucagon stimulation in the two periods of treatment (SU: 1.70 +/- 0.72, insulin: 1.47 +/- 0.98 ng/ml). In group B patients (n = 7), there was no significant difference in glycemic control after transferring the treatment from insulin to SU (fasting plasma glucose: insulin: 127 +/- 24, SU: 103 +/- 13 mg/dl). Fasting serum CPR was significantly lower during the period of insulin treatment (insulin: 1.39 +/- 0.64, SU: 2.21 +/- 0.86 ng/ml, p less than 0.025), but delta serum CPR during glucagon stimulation still showed no significant difference between the two periods (insulin: 1.97 +/- 1.16, SU: 2.33 +/- 1.57 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
K Iwamoto M Takeishi K Takagi T Kuyama M Yukawa M Ishida T Kuramochi 《Cellular and molecular biology, including cyto-enzymology》1989,35(3):271-278
The murine monoclonal antibodies RPA-T4 and HuLy-m8, specific for a framework determinant of human helper/inducer and suppressor/cytotoxic T cell antigens, cross-reacted with canine cell membrane molecules recognizing a biomolecular complex (50,000 to 55,000 daltons) similar to that described in humans. We investigated the distribution of these helper and suppressor T cell-like antigens on canine peripheral blood lymphocytes. With complement-mediated lymphocytotoxicity, 34% and 35% of the canine lymphocytes expressed the helper T cell-like antigens and the suppressor-like T cell antigens, respectively. When the lymphocytes were treated with RPA-T4 and HuLy-m8, the respective helper and suppressor function was significantly inhibited. 相似文献
9.
10.
Summary Monoclonal antibodies were raised against germinal vesicles which were isolated from fully grown oocytes of the ascidianHalocynthia roretzi. Immunoblot analyses revealed that one of the antibodies, designated Hgv-2, recognized a single band with a molecular weight of about 83 kDa. The antibody, visualized by indirect immunohistochemistry, reacted only with the germinal vesicles of oocytes and did not react with test cells, follicle cells, and other somatic cells of the gonad. During embryogenesis the antigenicity was found in interphase nuclei of all embryonic cells. The antibody did not react with chromosomes or the mitotic apparatus. The antigenicity was retained by interphase nuclei of larval cells, but it disappeared from nuclei of juveniles about 7 days after metamorphosis. 相似文献