全文获取类型
收费全文 | 399篇 |
免费 | 27篇 |
国内免费 | 12篇 |
专业分类
438篇 |
出版年
2013年 | 9篇 |
2011年 | 10篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2000年 | 4篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1983年 | 4篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 10篇 |
1972年 | 8篇 |
1971年 | 7篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 5篇 |
1959年 | 15篇 |
1958年 | 25篇 |
1957年 | 12篇 |
1956年 | 17篇 |
1955年 | 12篇 |
1954年 | 7篇 |
1953年 | 5篇 |
1952年 | 8篇 |
1951年 | 10篇 |
1950年 | 14篇 |
1949年 | 10篇 |
1948年 | 9篇 |
排序方式: 共有438条查询结果,搜索用时 0 毫秒
21.
JOHNSTONE O. YOUNG 《Freshwater Biology》1972,2(3):253-258
Macrostomwn johni sp. nov. from Llyn Cwellyn, N. Wales is described. The species has been recorded from the vegetational littoral in December and February only. The main distinguishing criterion is the penis stylet which consists of a funnel, about 80-98 μm in length in slightly squashed specimens, curved in two planes and with a sub-terminal distal opening, the distal end is blunt and cowl (hood) shaped. Other features include the presence of sensory hairs and rhabdoids all over the body, ‘Haft-papillen’, and eyes. Rhammite tracks are weakly developed. The testes are elongate and the ovaries are compact, though slightly indented, and smaller than the testes. A very short ductus intervesicularis is present. The vagina is short. A ‘Verschlussap-parat’ is present but poorly developed. 相似文献
22.
23.
This study evaluated the results of fine needle aspiration cytology (FNAC) from the first four years of organized mammography screening for breast cancer in Oslo, particularly our policy in differentiating in situ and invasive carcinoma. Lesions were aspirated directly, ultrasound guided, by stereotaxic device or biopsy localization plate. All lesions were aspirated by cytopathologists working with the radiologists at the breast diagnostic centre. Smears were evaluated immediately for assessment of adequacy and a preliminary diagnosis was given to the surgeon. When FNAC revealed malignancy, diagnostic terms were as follows: (1) invasive carcinoma; (2) ductal carcinoma in situ of comedo type (high nuclear grade), cannot evaluate infiltration; (3) ductal carcinoma in situ of low nuclear grade and (4) papillary tumour, cannot evaluate infiltration. There were 953 cases, 70% of which were nonpalpable. Insufficient material was obtained in 5.8%. Absolute and complete sensitivity were 81% and 91%, respectively. Specificity was 85%. There were 448 histologically proven carcinomas. 383 of these were invasive. 362 carcinomas (in situ and invasive) (80.8%) were diagnosed directly on FNAC. Distinction between invasive and in situ carcinoma was possible in 294 of 320 directly diagnosed invasive carcinomas (91.8%). PPV of a diagnosis of invasive carcinoma was 97%. Our data showed that definitive cytological diagnosis of invasive carcinoma was possible in more than 90% of fully diagnostic smears and allowed definitive primary surgery in these women. 相似文献
24.
25.
26.
A technique is described to accurately assess the dermal contactdose-mortality response of molluscicides. The technique involvescarbon dioxide anaesthesia of laboratory reared Deroceras reticulatum(Müller) followed by application of test substances insolution to the dorsal surface. The LD50 of the substances testedwere as follows: Sodium pentachlorophenate, 55.9 ng.mg1,Copper sulphate, 124.1 ng.mg1, Methiocarb, 314.6 ng.mg1and Potassium permanganate, 418.9 ng.mg1 body weight. (Received 18 August 1988; accepted 17 December 1988) 相似文献
27.
R Moriggi Jr HS Di Mauro SC Dias JM Matos MB Urtado NF Camar?o IV Sousa Neto DC Nascimento RA Tibana CO Assump??o J Prestes CB Urtado 《Biology of sport / Institute of Sport》2015,32(4):289-294
Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances. 相似文献
28.
29.
30.