首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8289篇
  免费   899篇
  国内免费   6篇
耳鼻咽喉   135篇
儿科学   256篇
妇产科学   109篇
基础医学   1170篇
口腔科学   321篇
临床医学   821篇
内科学   1621篇
皮肤病学   147篇
神经病学   590篇
特种医学   350篇
外科学   1096篇
综合类   185篇
一般理论   10篇
预防医学   1116篇
眼科学   269篇
药学   558篇
中国医学   13篇
肿瘤学   427篇
  2021年   106篇
  2020年   79篇
  2019年   114篇
  2018年   135篇
  2017年   97篇
  2016年   96篇
  2015年   117篇
  2014年   157篇
  2013年   276篇
  2012年   348篇
  2011年   364篇
  2010年   221篇
  2009年   208篇
  2008年   355篇
  2007年   382篇
  2006年   369篇
  2005年   418篇
  2004年   381篇
  2003年   387篇
  2002年   386篇
  2001年   222篇
  2000年   278篇
  1999年   192篇
  1998年   126篇
  1997年   134篇
  1996年   108篇
  1995年   114篇
  1994年   84篇
  1993年   77篇
  1992年   151篇
  1991年   155篇
  1990年   151篇
  1989年   144篇
  1988年   131篇
  1987年   127篇
  1986年   141篇
  1985年   139篇
  1984年   121篇
  1983年   103篇
  1982年   83篇
  1981年   101篇
  1980年   78篇
  1979年   84篇
  1978年   80篇
  1977年   50篇
  1976年   72篇
  1975年   72篇
  1974年   68篇
  1973年   83篇
  1972年   54篇
排序方式: 共有9194条查询结果,搜索用时 15 毫秒
41.
Glycinebetaine has previously been shown to be effective at reducing leakage from liposomes which are frozen then thawed. This study involved the preparation of a series of N-modified betaines and the comparison of their cryoprotective activities with those of glycine, sarcosine, N,N-dimethylglycine and glycinebetaine. All the compounds investigated, with the exception of (dimethyloctylammonio)acetate, reduced the degree of leakage, after freezing and thawing, with additive concentrations up to 0.6 M. Reducing the degree of N-terminal methylation of glycinebetaine appeared to increase the leakage from liposomes at additive concentrations between 0.2 and 0.6 M. (Dimethylethylammonio)acetate, (dimethylisopropylammonio)acetate and (N,N,N',N'-tetramethylethylenediammonio)-N,N'-diacetate appeared to be no more effective than glycinebetaine, whereas improved protection was afforded by (triethylammonio)acetate and (diethylmethylammonio)acetate at most concentrations. This study demonstrates that the cryoprotective activity of glycinebetaine may be improved with modifications to the N-terminal.  相似文献   
42.
43.
Conclusion The saga of the Society—from Kocher to Allgöwer-rings with true accomplishment. As we near the end of our first complete century, we can look back with a sense of satisfaction. At the same time we must recognize that there still is much to do.I wish to paraphrase the words of Kocher's 1905 inaugural address:Presidential address to the opening of the Scientific Program of the International Society of Surgery/Société Internationale Chirurgie (ISS/SIC), August 23, 1993, Hong Kong.  相似文献   
44.
Plasma biochemical and haematological parameters were examined in 4-week-old to 12-week-old game birds. Healthy, uninfected pheasants and partridges had similar levels of total protein, albumin, osmolality, Na+, Cl-, K+, Mg2+ and glucose. Triglyceride, globulin and Ca2+ were significantly higher and PO43- was lower in the partridges. Pheasants carrying a light to moderate infection with Spironucleus had significantly lower total protein, albumin, osmolality, Na+, Cl-, Ca2+ and PO43-. In severely affected pheasants, the osmolality, Na+ and Cl- fell further. Triglyceride and glucose were significantly lower than in healthy birds, and Mg2+ was higher. Similar data were obtained from infected partridges. Red cell parameters rose significantly in pheasants severely affected by spironucleosis, and the percent of heterophils was significantly higher and lymphocytes and basophils lower in their blood smears. The breast and leg muscle wet weight from severely affected pheasants was 22.2 and 37.7% that of uninfected birds, although the water content of the breast muscle was significantly higher.  相似文献   
45.
46.
The efficacy of a single dose of intramuscular ketorolac 10 mg or 90 mg was compared with pethidine 100 mg in a randomized double-blind study in 121 patients reporting at least moderate pain due to renal colic. Pain was assessed before drug administration, and then at 1 hour and 12 hours after the dose. Sedation was also assessed at these times, and additionally at the 12 hour assessment the time of the next analgesic dose was recorded. At 1 hour after dosing, pain scores had decreased in all groups; the largest decrease was seen in the ketorolac 90 mg group. The difference in the decrease was significant between the two ketorolac groups, but the differences between ketorolac and pethidine were not significant. Fewer patients in the ketorolac 90 mg group (17%) required a further dose of analgesic within 10 hours than in either the ketorolac 10 mg group (39%) or the pethidine 100 mg group (47%). The difference between ketorolac 90 mg and pethidine 100 mg was statistically significant. At both assessment times the proportion of patients with no sedation was higher in the two ketorolac groups than in the pethidine group. The overall incidence of adverse events was low with all drugs, notably so for the occurrence of vomiting after ketorolac. The results of the study show that intramuscular ketorolac is efficacious in the treatment of renal colic.  相似文献   
47.
48.
49.
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号