全文获取类型
收费全文 | 1803320篇 |
免费 | 231778篇 |
国内免费 | 30536篇 |
专业分类
2065634篇 |
出版年
2018年 | 18248篇 |
2017年 | 17156篇 |
2016年 | 24137篇 |
2015年 | 32451篇 |
2014年 | 37659篇 |
2013年 | 53329篇 |
2012年 | 59446篇 |
2011年 | 60619篇 |
2010年 | 43076篇 |
2009年 | 43155篇 |
2008年 | 55104篇 |
2007年 | 56634篇 |
2006年 | 51935篇 |
2005年 | 50380篇 |
2004年 | 49986篇 |
2003年 | 47662篇 |
2002年 | 47006篇 |
2001年 | 73247篇 |
2000年 | 71816篇 |
1999年 | 60457篇 |
1998年 | 26769篇 |
1997年 | 25789篇 |
1996年 | 24278篇 |
1995年 | 23182篇 |
1994年 | 22579篇 |
1993年 | 22203篇 |
1992年 | 50807篇 |
1991年 | 49362篇 |
1990年 | 48499篇 |
1989年 | 47492篇 |
1988年 | 43878篇 |
1987年 | 42119篇 |
1986年 | 39281篇 |
1985年 | 39559篇 |
1984年 | 33184篇 |
1983年 | 28650篇 |
1982年 | 22934篇 |
1981年 | 20873篇 |
1980年 | 19695篇 |
1979年 | 31927篇 |
1978年 | 25461篇 |
1977年 | 23372篇 |
1976年 | 22039篇 |
1975年 | 24043篇 |
1974年 | 26518篇 |
1973年 | 26027篇 |
1972年 | 23801篇 |
1971年 | 21870篇 |
1970年 | 19049篇 |
1969年 | 18428篇 |
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
41.
Y Tani I Ohkubo S Higashiyama M Kunimatsu M Sasaki 《Comparative biochemistry and physiology. B, Comparative biochemistry》1987,88(2):429-441
1. High mol. wt kininogen (HMW kininogen) was purified to a homogeneous state from porcine plasma. 2. The protein exhibited a strong inhibitory activity for thiol proteinases such as ficin, papain and calpain I, whereas it did not inhibit serine proteinases, trypsin and chymotrypsin. 3. The mol. wt, isoelectric point, amino acid and carbohydrate compositions, stabilities to temperature and pH, kinetic constants, and immunological properties of the porcine HMW kininogen were determined and compared with those of human HMW kininogen. 相似文献
42.
B B Fuks N F Avrova L V Van'ko N A Starosvetskaia M N Boltovskaia 《Biulleten' eksperimental'no? biologii i meditsiny》1986,101(1):66-68
Female BALB/c mice were immunized with human melanoma (Mewo) cells containing ganglioside GD3 as a surface antigen. Immune splenocytes were fused with syngeneic P3-X63.Ag 8 myeloma cells. Antibodies produced by hybrid clones were analyzed by solid phase immunoassay. B, C, D and Q clones producing antibodies against Raja clavata brain gangliosides were obtained. Monoclonal B and C antibodies bound monosialogangliosides. Monoclonal D antibody bound a number of gangliosides but reacted predominantly with GD1a. Monoclonal Q antibody reacted selectively with GQ1c. It is assumed that ganglioside GQ1c is expressed on the melanoma cell surface and may be found only in the early stage of ontogenesis of high vertebrates. 相似文献
43.
M C Bateson 《BMJ (Clinical research ed.)》1984,289(6453):1163-1164
44.
45.
46.
Training-induced bradycardia and intrinsic heart rate in rats 总被引:1,自引:0,他引:1
E Nylander K Sigvardsson A Kilbom 《European journal of applied physiology and occupational physiology》1982,48(2):189-199
After 10 weeks of treadmill training, female Sprague-Dawley rats had developed a bradycardia at exercise on submaximal work loads. This bradycardia was also present after autonomic denervation and in isolated perfused heart preparations. The heart weight/body weight ratio was increased in these trained animals compared to untrained littermates. Sympathectomized, trained rats developed the same degree of cardiac hypertrophy, but their heart rate after denervation and in the isolated heart was the same as in sympathectomized, untrained rats. It is concluded that the bradycardia of trained and thereafter denervated animals seen in this and a previous investigation represents an adaptation within the heart itself, since it was present in the isolated heart. These results thus provide further evidence for a non-neural component in training-induced bradycardia. Since the trained sympathectomized rats had a cardiac hypertrophy but no reduction of intrinsic heart rate, it seems likely that the myocardial mass is of minor importance for the level of intrinsic heart rate. 相似文献
47.
S Kh Khaduev O S Zhukova Ia V Dobrynin K Soda T T Berezov 《Biulleten' eksperimental'no? biologii i meditsiny》1986,101(5):603-604
L-lysine-alpha-oxidase, a new fungal enzyme catalyzing oxidative deamination of L-lysine, exerts an inhibitory effect on DNA, RNA and protein synthesis in human cells of carcinoma ovarius (CaOv) in vitro. 相似文献
48.
L J Petterborg M K Vaughan L Y Johnson T H Champney R J Reiter 《Comparative biochemistry and physiology. A, Comparative physiology》1984,78(1):31-34
Exposure of male Syrian hamsters (Mesocricetus auratus) for 10 weeks to short photoperiod (SP) providing 10 hr light: 14 hr darkness (10:14 LD) produced a significant reduction in the weights of the reproductive organs, plasma thyroxine (T4) levels and free T4 index (FT4I) compared to the values of animals exposed to long photoperiod (LP, 14:10 LD). C57bl male house mice (Mus musculus) kept in SP (10:14 LD) had reproductive organ weights equivalent to those of mice kept in long days (14:10 LD) and lower T3 uptake (T3U) values. Male gerbils (Meriones unguiculatus) exposed to 13 weeks of SP (10:14 LD) had lower body weights, testes and seminal vesicle weights and higher T3U values compared to LP (14:10 LD) controls. However, no effect was seen on plasma T4 and triiodothyronine (T3) values nor the FT4I and free T3 index (FT3I). White-footed male mice (Peromyscus leucopus) exposed to SP (8:16 LD) had significantly lower testes and seminal vesicle weights while plasma T4 and T3 levels were unaffected. Snell strain house mice (Mus musculus) exposed to SP (8:16 LD) had normal reproductive organ weights compared to the values of LP-exposed (16:8 LD) control animals. However, there was a significant depression in T3 and in the FT3I in the SP animals. 相似文献
49.
50.
Airway area by acoustic reflections measured at the mouth 总被引:5,自引:0,他引:5
Fredberg J. J.; Wohl M. E.; Glass G. M.; Dorkin H. L. 《Journal of applied physiology》1980,48(5):749-758