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   3746篇
  免费   91篇
  国内免费   1篇
林业   2267篇
农学   23篇
基础科学   5篇
  173篇
综合类   13篇
农作物   177篇
水产渔业   61篇
畜牧兽医   908篇
园艺   41篇
植物保护   170篇
  2014年   35篇
  2013年   110篇
  2011年   30篇
  2010年   44篇
  2009年   48篇
  2008年   34篇
  2006年   38篇
  2005年   83篇
  2004年   82篇
  2003年   62篇
  2002年   49篇
  2001年   35篇
  2000年   33篇
  1997年   49篇
  1996年   75篇
  1995年   52篇
  1994年   54篇
  1993年   65篇
  1992年   74篇
  1991年   54篇
  1990年   44篇
  1989年   39篇
  1988年   49篇
  1987年   40篇
  1986年   51篇
  1985年   34篇
  1984年   50篇
  1983年   53篇
  1982年   60篇
  1981年   107篇
  1980年   53篇
  1979年   83篇
  1978年   43篇
  1954年   36篇
  1953年   61篇
  1938年   58篇
  1937年   47篇
  1936年   49篇
  1935年   49篇
  1934年   48篇
  1933年   53篇
  1932年   48篇
  1931年   38篇
  1930年   37篇
  1929年   31篇
  1928年   33篇
  1927年   44篇
  1926年   74篇
  1925年   55篇
  1898年   33篇
排序方式: 共有3838条查询结果,搜索用时 11 毫秒
71.
The radiographic appearance of the cribriform plate was investigated in 16 canine cadaver heads. The cribriform plate appeared as a "V"-shaped multilinear bone-opaque stripe in the caudal nasal region in projections perpendicular to the hard palate in 6 dogs with a skull index between 50.00 and 54.00. In 9 dogs with a skull index between 55.40 and 74.40, the cribriform plate had a more "C"-shaped and sharp appearance. In vertically oblique projections with an obliquity greater than 20 degrees, the cribriform plate lost its sharp outline and finally (40 degrees) disappeared. In lateral projections the cribriform plate appeared as a "C"-shaped interrupted bone-opaque stripe in all 16 dogs. In more brachycephalic dogs frontal bone structures superimposed on the cribriform plate on ventrodorsal and dorsoventral views and accentuated the radiographic appearance of the plate. Vertically oblique views separated both structures to produce two lines.  相似文献   
72.
73.
74.
The purpose of this study was to evaluate the applicability of ultrasonographic imaging of the vagosympathetic trunk in the dog. Cervical ultrasound was performed in 30 healthy dogs. In all 30 dogs the vagosympathetic trunk was detected as a hypoechoic structure in the carotid sheath, adhering the dorsomedial surface of the common carotid artery. The echotexture of the nerve was heterogeneous with anechoic areas separated by hypoechoic bands. A scanner equipped with a 5 to 8 MHz linear array probe was used for imaging and measurements. The diameter of the vagosympathetic trunk ranged from 0.59 to 2.48 mm varying in correlation to the body weight. In summary, ultrasonography is a helpful noninvasive method to image and evaluate the cervical vagosympathetic trunk in the dog.  相似文献   
75.
76.
77.
78.
79.
Objective— To describe an extra-articular joint distractor for meniscal examination and treatment during canine stifle arthroscopy.
Study Design— Case series.
Animals— Dogs ≥20 kg with suspected cranial cruciate ligament (CrCL) deficiency.
Methods— A custom designed linear side bar was constructed to allow invasive pin distraction of the stifle joint. Its design efficacy for distraction of the medial joint compartment, observation and probing of the medial meniscus, and value during meniscal surgery was evaluated by clinical use.
Results— Application of the stifle distractor medial to the stifle joint using 2 negative threaded pins was easily performed percutaneously without the need of power equipment; however, unintended intra-articular placement of 1 threaded pin occurred in 2 stifles, without appreciable consequence to joint function. Observation as well as thorough probing of the caudal horn of the medial meniscus, even in the presence of a prominent remnant of the CrCL or severe periarticular fibrosis, was possible. Partial meniscectomy was effectively performed as needed without apparent damage to the associated articular surfaces.
Conclusions— Distraction and translation of the medial compartment of the stifle joint using invasive pin distraction allowed observation and palpation of the caudal horn of the medial meniscus so that assessment and treatment were readily accomplished without apparent morbidity.
Clinical Relevance— With careful attention to accurate pin placement, invasive pin distraction of the medial compartment of the canine stifle joint may improve arthroscopic evaluation and treatment of meniscal pathology.  相似文献   
80.
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