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   23802篇
  免费   2207篇
  国内免费   33篇
耳鼻咽喉   234篇
儿科学   702篇
妇产科学   593篇
基础医学   2774篇
口腔科学   442篇
临床医学   2470篇
内科学   4898篇
皮肤病学   393篇
神经病学   2207篇
特种医学   942篇
外国民族医学   3篇
外科学   3541篇
综合类   543篇
一般理论   43篇
预防医学   2524篇
眼科学   310篇
药学   1561篇
中国医学   35篇
肿瘤学   1827篇
  2022年   146篇
  2021年   361篇
  2020年   207篇
  2019年   402篇
  2018年   532篇
  2017年   384篇
  2016年   351篇
  2015年   439篇
  2014年   600篇
  2013年   899篇
  2012年   1183篇
  2011年   1211篇
  2010年   797篇
  2009年   711篇
  2008年   1136篇
  2007年   1220篇
  2006年   1213篇
  2005年   1175篇
  2004年   1076篇
  2003年   1005篇
  2002年   920篇
  2001年   616篇
  2000年   637篇
  1999年   576篇
  1998年   348篇
  1997年   266篇
  1996年   278篇
  1995年   284篇
  1994年   207篇
  1993年   210篇
  1992年   438篇
  1991年   426篇
  1990年   375篇
  1989年   382篇
  1988年   353篇
  1987年   338篇
  1986年   303篇
  1985年   314篇
  1984年   270篇
  1983年   235篇
  1982年   174篇
  1981年   163篇
  1979年   241篇
  1978年   176篇
  1977年   153篇
  1974年   150篇
  1973年   190篇
  1972年   186篇
  1971年   159篇
  1969年   147篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The authors compared 57 patients with multiple personality disorder (MPD) who had been hypnotized both before and after diagnosis to 38 patients who had not been hypnotized during assessment or treatment. The two groups did not differ on the diagnostic criteria for MPD or in number of personalities. Hypnosis therefore does not have a gross distorting effect on the features of the disorder. Hypnosis may, however, affect the recall of sexual and physical abuse and the manifestation of certain types of alter personality. These include child personalities, personalities of different age, sex, or race, and protectors. The authors hypothesize that the hypnotized group may require hypnosis for access of more traumatic memories held by child personalities.  相似文献   
62.
63.
Summary 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a potent inducer of monocytic differentiation of the human promyelocytic leukemia cell line, HL-60. We have noted that 25-hydroxyvitamin D3 (25(OH)D3) in high doses is also capable of promoting monocytic differentiation of this cell line. To test the possibility that the latter activity is due to conversion of 25OHD3 to 1,25(OH)2D3 by HL-60, we exposed HL-60 cells to 25OHD3 and analyzed the products by HPLC and radioreceptor assay. When chromatographed in the traditional solvent system (isopropanol-hexane), a new peak appears which migrates with authentic 1,25(OH)2D3. However, in a solvent system containing dichloromethane, 90% of the peak migrates with another metabolite, 19-Nor-10-Keto-25OHD3 (19-Nor-25OHD3). Production of this metabolite is enhanced by living cells and is synthesized by both virgin HL-60 and those which have undergone differentiation. We next determined if authentic 19-Nor-25OHD3 also promotes differentiation of this cell. As assessed by appearance of the monocyte-specific surface antigen (63D3) and macrophage-specific esterase activity, we find that this metabolite does, in fact, induce monocytic differentiation of HL-60 with a potency of approximately 1/200 that of 1,25(OH)2D3 and similar to that of 25OHD3. In agreement with the effect upon cell maturation, 19-Nor-25OHD3 displaces3H-1,25(OH)2D3 from its HL-60 receptor with an efficiency comparable to 25OHD3. Hence, HL-60 cells convert 25OHD3 to 19-Nor-25OHD3, and 19-Nor-25OHD3 induces monocytic differentiation of HL-60 with comparable efficiency to its precursor, 25OHD3.  相似文献   
64.
The clinical functions of the posterior columns of the spinal cord and the signs of disease of these structures have been debated for years. Todd in 1847 and Schiff in 1858 knew the functions of the posterior columns and 10 years later Brown-Séquard knew as well. Reynolds, Romberg, and Duchenne, each described a posterior column syndrome based on a disease in which the primary lesion was not in the posterior columns. In the last 150 years almost every white matter structure of the cord has been credited with serving the sensations that we now know are a function of the posterior columns. Vibration, joint position and movement as well as discriminatory touch each seem to be served by separate fibres of the posterior columns and medial lemniscus. There is evidence of this in cat and man. These sensations may be lost individually, totally, or in certain stereotyped combinations. Vibration or joint sense is commonly lost alone. When a discriminatory touch sensation is lost with one other sense, it is almost inevitably joint position sense. Absent discriminatory touch and vibration sense with normal joint position sense appears to be unknown. This functional separation continues into the thalamus. At the highest level there is no evidence that vibration sense has any conscious somatosensory cortical affiliation, while joint position and discriminatory touch senses definitely do.  相似文献   
65.
66.
67.
68.
A 36-year-old woman with newly diagnosed acne rosacea is presented. Her skin changes were noticeable only under closest scrutiny, but she quit her job, became despondent about her acne, and developed suicidal ideation. The diagnosis and treatment of this patient allow a broader discussion of the somatically focused patient whose ideation reaches delusional intensity.  相似文献   
69.
Daily administration of an escalating dose of tumour necrosis factor-alpha (TNF-alpha) to female NMRI mice caused a progressive loss of body weight representing 12% of the original weight over a 6-day period. Weight loss was associated with a decreased food intake and pair-fed controls exhibited a weight loss of similar magnitude to that caused by TNF-alpha. However, weight loss in animals bearing a murine adenocarcinoma (MAC16) occurred without a change in energy intake and thus differed from that produced by TNF-alpha. Anti-TNF-alpha monoclonal antibodies at levels capable of protecting mice against lethal endotoxaemia were ineffective in reversing weight loss in animals bearing the MAC16 tumour and had no effect on the increase in tumour volume. Circulating levels of interleukin-6 were not elevated in animals bearing the MAC16 tumour and with a weight loss between 1.8 and 5.4 g. These results suggest that these cytokines are not involved in the cachexia produced by this murine tumour.  相似文献   
70.
A basic theory of nonspecific toxicity has been developed using bioconcentration as a basis and applying kinetic relationships developed in previous work. This approach has involved calculation of the critical volume fraction and critical concentration in lipid tissue of fish for a variety of organic compounds at the lethal level. Corrections to previous data sets for time period of exposure and inclusion of biodegradable compounds did not make a significant improvement in the values obtained. A new data base with compounds containing a wide range of Kow values gave results for critical volume and concentration similar to previous work. The influence of experimental procedures and methods for data development are considered. The basic theoretical derivation developed was found to provide a basis for predicting the approximate nonspecific toxicity of nondegradable lipophilic organic compounds at different exposure time periods. This requires a knowledge of the Kow value and the clearance rate constant (k2) which can be calculated from the Kow value.  相似文献   
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