全文获取类型
收费全文 | 7267篇 |
免费 | 378篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 75篇 |
妇产科学 | 162篇 |
基础医学 | 887篇 |
口腔科学 | 194篇 |
临床医学 | 398篇 |
内科学 | 1594篇 |
皮肤病学 | 132篇 |
神经病学 | 605篇 |
特种医学 | 209篇 |
外科学 | 1475篇 |
综合类 | 27篇 |
预防医学 | 280篇 |
眼科学 | 383篇 |
药学 | 547篇 |
中国医学 | 16篇 |
肿瘤学 | 661篇 |
出版年
2023年 | 43篇 |
2021年 | 118篇 |
2020年 | 72篇 |
2019年 | 95篇 |
2018年 | 135篇 |
2017年 | 109篇 |
2016年 | 125篇 |
2015年 | 110篇 |
2014年 | 186篇 |
2013年 | 232篇 |
2012年 | 339篇 |
2011年 | 375篇 |
2010年 | 197篇 |
2009年 | 199篇 |
2008年 | 335篇 |
2007年 | 372篇 |
2006年 | 351篇 |
2005年 | 402篇 |
2004年 | 352篇 |
2003年 | 361篇 |
2002年 | 321篇 |
2001年 | 247篇 |
2000年 | 272篇 |
1999年 | 233篇 |
1998年 | 88篇 |
1997年 | 64篇 |
1996年 | 69篇 |
1995年 | 54篇 |
1994年 | 53篇 |
1993年 | 40篇 |
1992年 | 168篇 |
1991年 | 149篇 |
1990年 | 132篇 |
1989年 | 138篇 |
1988年 | 140篇 |
1987年 | 128篇 |
1986年 | 132篇 |
1985年 | 121篇 |
1984年 | 87篇 |
1983年 | 51篇 |
1982年 | 35篇 |
1980年 | 25篇 |
1979年 | 42篇 |
1978年 | 36篇 |
1977年 | 32篇 |
1974年 | 34篇 |
1973年 | 26篇 |
1972年 | 31篇 |
1970年 | 25篇 |
1969年 | 28篇 |
排序方式: 共有7681条查询结果,搜索用时 125 毫秒
21.
The aim of this study was to determine if cAMP regulates the proliferation of chicken granulosa cells and if there is a difference in the effects of cAMP on the granulosa cell proliferation between the largest follicle (F1) and the smaller follicles. Granulosa cells collected from F1 and the third largest follicle (F3) were cultured in medium M199 containing 1% calf serum with or without dibutyryl cAMP (dbcAMP). Proliferation of granulosa cells of F1 was promoted by dbcAMP in a dose-dependent manner. The most effective concentration of dbcAMP to promote the granulosa cell proliferation was 2 mM. In the culture without dbcAMP, the number of the granulosa cells was not changed significantly for 6 days, whereas, in the presence of 2 mM dbcAMP, the number of the granulosa cells was markedly increased during 2 to 6 days. The proliferation of the granulosa cells of F3 was stimulated by dbcAMP in the same manner as that of F1. Morphologically, the granulosa cells of F1 and F3 cultured for 2 days had a sheet-like appearance in control culture, whereas they were contracted, leaving finger-like cytoplasmic processes attached to the adjacent cells and substratum in the presence of 2 mM dbcAMP. After 6 days culture, approximately 90% of the cells of F1 stained positive for 3 beta-hydroxysteroid dehydrogenase activity in 2 mM dbcAMP-containing culture, whereas only about 20% of the cells were positive in control culture. These results suggest that cAMP promotes the proliferation of the granulosa cells during the follicular growth and this response of granulosa cells to cAMP is similar for F1 and F3. 相似文献
22.
Investigation of association of mycobacteria with inflammatory bowel disease by nucleic acid hybridization. 总被引:11,自引:3,他引:8 下载免费PDF全文
We used DNA-DNA hybridization to characterize a mycobacterial isolate, strain Linda, that was obtained from a patient with Crohn's disease and that has been reported to cause ileitis in experimental animals. We also investigated the association of this mycobacterium with Crohn's disease. Our results identified Mycobacterium strain Linda as a strain of Mycobacterium paratuberculosis, the etiologic agent of Johne's disease, a disease of ruminants that has some superficial resemblance to Crohn's disease. Sequences that hybridized with strain Linda DNA probes were detected in DNA extracted from human intestinal tissues from patients with Crohn's disease, ulcerative colitis, and noninflammatory bowel disease. These hybridizing DNA sequences were more prevalent in the muscle layers than in the intestinal mucosa, making it unlikely that they represented DNA from bacterial contaminants in the intestinal lumen. Measurement of the melting temperatures of the DNA-DNA hybrids formed between strain Linda probes and tissue DNAs indicated that the related sequences detected were of mycobacterial origin but were not identical to each other or to strain Linda DNA. These results do not support the proposed specific relationship between Mycobacterium strain Linda and Crohn's disease. The possible etiologic role of mycobacteria in Crohn's disease is discussed. 相似文献
23.
24.
Contraction of urinary bladder by central norepinephrine originating in the locus coeruleus 总被引:3,自引:0,他引:3
Studies were performed to elucidate the role of the locus coeruleus, which is rich in norepinephrine-containing cell bodies, in vesical function using alpha-chloralose anesthetized cats. Stimulation of the locus coeruleus caused contraction of the urinary bladder, which was not affected by transection of the bilateral hypogastric nerves, but blocked by intravenous administration of hexamethonium, a ganglion blocking agent. In animals with transected hypogastric nerves, the locus coeruleus-induced contraction was inhibited by intrathecal administration of phentolamine (alpha-blocker) and prazosin (alpha 1-blocker), but not affected by intrathecal sotalol (beta-blocker) or yohimbine (alpha 2-blocker). In animals treated with reserpine, the locus coeruleus-induced contraction was enhanced by intravenous application of L-dopa, a precursor of norepinephrine. These results suggest that norepinephrine derived from the locus coeruleus activated preganglionic neurons in the sacral intermediolateral nuclei via alpha 1-receptors, thereby producing urinary bladder contraction. 相似文献
25.
Masayoshi Johno Munashi Oishi Masahiro Kohmaru Kohji Yoshimura Tomomichi Ono 《The Journal of dermatology》1994,21(3):197-204
A boy with skin eruptions resembling varicella and specific for Langerhans cell histiocytosis (LCH) is reported. At his initial visit when he was four months old, vesiculopustular lesions were present over the entire body; these had first appeared on the third day post partus. Histopathological, immunohistochemical, and electron microscopical examination confirmed the Langerhans cell phenotype and Birbeck granules in the responsible cells. He also had hydronephrosis, recurrent fever, and cutaneous bacterial infections. His parents refused further medical treatment and he died of diarrhea with cachexia about two years later. LCH may present diagnostic difficulties by manifesting as a skin eruption which resembles varicella. 相似文献
26.
27.
28.
K Fujikawa H Onishi N Yoshimura Y Arai T Hashimura O Yoshida 《Hinyokika kiyo. Acta urologica Japonica》1992,38(10):1179-1182
Sacral agenesis is an uncommon disease. About 50 cases have been reported in Japan since 1929. Neurogenic bladder is often accompanied with the disease. The patient was a 26-year-old man who had suffered from persistent urinary incontinence since his childhood. Kidney-ureter-bladder (KUB) revealed Type IV sacral agenesis according to the classification by Renshaw. The upper urinary tract remained normal. Urodynamics study showed a low compliance bladder with low urethral pressure. Pharmacotherapy failed to improve his continence. Augmentation sigmoid-cystoplasty was undertaken to enlarge vesical capacity and it has successfully overcome his urinary incontinence. Clinical aspects of sacral agenesis are discussed focusing on urological problems. 相似文献
29.
T Oda S Yoshimura T Hara S Hara M Yahagi C Matsumoto T Ohno Y Nakamura Y Sumi K Sueoka 《Nippon Sanka Fujinka Gakkai zasshi》1987,39(1):113-120
To examine the effects of transient hyperprolactinemia on in vitro fertilization and embryo transfer, 61 cycles in 50 euprolactinemic ovulatory women with irreparable tubal diseases were stimulated with clomiphene (CC) alone or CC and human menopausal gonadotropin followed by human chorionic gonadotropin (hCG). Serum prolactin (PRL) increased after hCG administration with peak values of 45.4 +/- 4.2 ng/ml on the day of laparoscopic oocyte aspiration. The highest serum estradiol (E2) concentration was found on the day before PRL peak and serum progesterone (P) began to increase after hCG injection concomitant with the PRL rise. The group having 50 ng/ml or more of PRL (34 cycles) had significantly higher levels of E2 during preovulatory and early luteal phase compared to those of the group having less than 50 ng/ml of PRL (27 cycles) but there was no significant difference between the P levels in the two groups. In the higher PRL group 72 (62.1%) of 116 collected oocytes were fertilized and 6 (20.0%) conceived. In the lower PRL group 45 oocytes (58.4%) of 77 were fertilized and 3 (12.5%) became pregnant. These data suggest that elevated serum PRL concentrations may have no effect on fertilization of oocytes in vitro or embryonic development. 相似文献
30.
Shun'Ichi Abe Hiroshi Yoshimura Hideki Tabara Mitsuo Tachibana Naomi Monden Teruhisa Nakamura Saburou Nagaoka 《Journal of surgical oncology》1995,59(4):226-229
Patients with stage T3N0~2M0 gastric carcinoma (n = 108) were studied for relevant prognostic factors. Peritoneal lavage cytology (PLC) was performed in all. In univariate analysis, 5-year survival rates were better with smaller serosal invasion (diameter <3.0 cm vs. ≥3.0 cm, 61% vs. 37%, P < 0.05) and fewer metastatic nodes (≤5 vs. ≥6, 57% vs. 29%, P < 0.05). In multivariate analyses, only these two factors were significant. The predictive value of PLC was not shown in both univariate and multivariate analyses. Peritoneal recurrence occured in 14 (22%) of 77 patients with negative PLC, and in 3 (18%) of 17 with positive PLC, the difference being not significant. Our results indicate that PLC is insensitive in predicting the development of peritoneal recurrence. Its role in the estimation of survival is limited, as many will die of visceral or locoregional recurrence if not of peritoneal dissemination. 相似文献