首页 | 官方网站   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   1797篇
  免费   103篇
  国内免费   10篇
医药卫生   1910篇
  2023年   9篇
  2022年   14篇
  2021年   21篇
  2020年   14篇
  2019年   16篇
  2018年   28篇
  2017年   29篇
  2016年   33篇
  2015年   48篇
  2014年   70篇
  2013年   65篇
  2012年   100篇
  2011年   124篇
  2010年   66篇
  2009年   48篇
  2008年   79篇
  2007年   66篇
  2006年   61篇
  2005年   86篇
  2004年   61篇
  2003年   65篇
  2002年   75篇
  2001年   56篇
  2000年   69篇
  1999年   59篇
  1998年   13篇
  1997年   16篇
  1996年   13篇
  1995年   10篇
  1994年   21篇
  1993年   14篇
  1992年   60篇
  1991年   41篇
  1990年   26篇
  1989年   34篇
  1988年   33篇
  1987年   38篇
  1986年   29篇
  1985年   27篇
  1984年   18篇
  1983年   18篇
  1982年   8篇
  1979年   14篇
  1978年   10篇
  1975年   9篇
  1974年   10篇
  1973年   12篇
  1971年   11篇
  1969年   13篇
  1967年   10篇
排序方式: 共有1910条查询结果,搜索用时 0 毫秒
1.
2.
The human soleus muscle is considered a specialized muscle in terms of its origin, insertion and muscle fibre architecture (especially with regard to the existence of the bipenniform part). Its peculiarities have been understood as results of erect posture and bipedal walking (Frey, 1913). Sekiya (1991) pointed out that another feature of the human soleus muscle the nerve supply, i.e. the muscle received two kinds of nerves, the anterior branch (R. anterior) and the posterior branch (R. posterior); the former supplied the bipenniform part at the anterior surface of the muscle and communicated with the R. posterior within the muscle. In nonhuman primates, the soleus muscle has no bipenniform part and the nerve, identical with the R. anterior to the human soleus muscle, is unknown. The purpose of the present study is to clarify the pattern of the nerve supply to the soleus muscle in the chimpanzee, with special reference to the intramuscular distribution of the nerves and to discuss the origin of the R. anterior to the human soleus muscle from a comparative anatomical point of view. Six soleus muscles from three chimpanzees (Pan troglodytes) were examined under a stereomicroscope to clarify the intramuscular distribution of nerves supplying these muscles. The nerves supplying the soleus muscle were classified into three types according to the sites of their entry into the muscle. The first group nerve was the thickest of all nerves innervating the muscle, entered the muscle at the posterior surface of the proximal third and was considered as homologous with the R. posterior in the human.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
Abstract: Studies on the circadian rhythm of urine excretion in healthy men have demonstrated that the maximal urine flow occurs in the early afternoon and the minimal around midnight. In this study, an abnormality in the variation of urine volume was found in parkinsonian patients. Urine samples were collected during daytime (9:00–21:00) and nighttime (21:00–9:00). Fifteen healthy control subjects were examined and found to excrete 60% during the daytime and 40% during the nighttime of the total urine volume. Sixteen parkinsonian patients excreted 43% during the daytime and 57% during the nighttime. In contrast to the control subjects, the parkinsonian patients excreted a smaller volume of their urine during the daytime than during the nighttime. This finding might be related to the degeneration of dopaminergic and/or nondopaminergic neurons in the brain which control urinary excretion.  相似文献   
4.
5.
Toluene in blood as a marker of choice for low-level exposure to toluene   总被引:1,自引:1,他引:0  
The validity of two new biological exposure markers of toluene in blood (TOL-B) and toluene in urine (TOL-U) was examined in comparison with that of the traditional marker of hippuric acid in urine (HA-U) in 294 male workers exposed to toluene in workroom air (TOL-A), mostly at low levels. The exposure was such that the geometric mean for toluene was 2.3 ppm with a maximum of 132 ppm; the workers were also exposed to other solvents such as hexane, ethyl acetate, styrene, and methanol, but at lower levels. The chance of cutaneous absorption was remote. Higher correlation with TOL-A and better sensitivity in separating the exposed workers from the nonexposed subjects were taken as selection criteria. When workers exposed to TOL-A at lower concentrations (< 50 ppm, < 10 ppm, < 2 ppm, etc.) were selected and correlation with TOL-A was examined, TOL-B showed the largest correlation coefficient which was significant even at TOL-A of < 1 ppm, whereas correlation of HA-U was no longer significant when TOL-A was < 10 ppm. TOL-U was between the two extremes. The sensitivities of TOL-B and TOL-U were comparable; HA-U showed the lowest sensitivity. Thus, it was concluded that TOL-B is the indicator of choice for detecting toluene exposure at low levels.  相似文献   
6.
7.
Kumaki et al. (1979) defined the extramural nerve as the rudimentary sensory nerve which appeared on the upper thoracic wall; it branched off the root of the lateral cutaneous nerve of the second, third or fourth intercostal nerve, ran inferomedially adhering to the fascia of the intercostalis externus muscle and ended supplying the membrane covering the adjacent rib. They also stated that the extramural nerve (Rxm) occasionally became a cutaneous nerve which pierced the pectoralis muscles and supplied the skin covering the thoracic wall similar to the lateral cutaneous nerve (Rcl) or the anterior cutaneous nerve (Rca). Further, they proposed that the muscular nerves to the obliquus externus abdominis muscle which are usually situated below the fifth rib might be considered a part of this Rxm series. Although the definition of Rxm is still not widely accepted, Rxm is thought to be a key morphological factor influencing the variations of peripheral nerve arrangement on the thoracic wall. In the student course of gross anatomy dissection at Iwate Medical University School of Medicine during the years 1987-1991, three cases of Rxm communicating with the pectoral nerve and supplying the pectoralis major muscle were observed. Some cases have been reported in which Rcl innervates part of the pectoral muscles. However, the communication between the pectoral nerve and Rxm has not yet been discussed. Therefore, to clarify the morphological significance of the communication between Rxm and the pectoral nerve, the branching pattern and the distribution of the pectoral nerves were extensively investigated and the intramuscular nerve supply of some pectoral nerves, especially the pectoral nerves which communicated with Rxm, was examined in detail under a stereomicroscope. The results are summarized as follows: 1. In the first case, Rxm of the second intercostal nerve originated from Rcl, ran inferomedially adhering to the fascia of the intercostalis externus muscle and pierced the origin of the pectoralis minor muscle at the third intercostal space. Then Rxm turned superolaterally to communicate with a pectoral nerve which originated from the loop composed of the lateral and medial pectoral nerves and passed inferior to the pectoralis minor muscle. After communication, the pectoral nerve with Rxm supplied the caudalmost part of the sternocostal portion of the pectoralis major muscle. In the second case, a similar branch of Rxm of the second intercostal nerve passed inferior to the pectoralis minor muscle.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
8.
Twenty-four adult cadavers (48 sides) were used to investigate the incidence of a branch arising from the ventral ramus of the fourth cervical nerve (C4) with the phrenic nerve and subsequently joining the brachial plexus. Six brachial plexuses with spinal cords and phrenic nerves were dissected under a surgical microscope to investigate localization of fibers contained in the C4 branch to the brachial plexus. The incidence of the C4 branch was 23% (11/48 sides). Branches from C4 to the brachial plexus divided into anterior and posterior divisions on four sides (4/6 sides). On two sides, the branch did not divide but consisted entirely of an anterior division (2/6 sides). In the brachial plexus, anterior division fibers of the C4 branch were intertwined with fibers from the anterior divisions of the ventral rami of the fifth and sixth cervical nerves. They then passed to the suprascapular nerve and the anterior division of the superior trunk (6/6 sides). On the other hand, posterior division fibers of the C4 branch were intertwined with fibers from the posterior divisions of the ventral rami of the fifth and sixth cervical nerves. They then passed to the suprascapular nerve (2/6 sides) and the posterior division of the superior trunk (4/6 sides). The anterior division of the C4 branch received fibers from the ventral rootlets of the entire fourth cervical segment, whereas the posterior division received fibers from the ventral rootlets of the caudal half of the fourth cervical segment only. The fact that the suprascapular nerve received fibers from both the anterior and posterior divisions of the C4 branch was considered to support our claim that the human suprascapular nerve belongs to both the anterior and posterior divisions of the brachial plexus.  相似文献   
9.
BACKGROUND: Japanese cedar and cypress pollen share a common antigen. The cedar pollen season is followed by the cypress pollen season. However, both the clinical significance and involvement of cypress pollinosis in the treatment of the cedar pollinosis have not yet been clarified. METHODS: The clinical efficacy of sublingual immunotherapy with cedar pollen extract for cedar pollinosis was evaluated during the cypress pollen dispersal season in Japan. In addition, the change in cypress pollen specific IgE antibodies of the patients with cedar pollinosis was examined before and after the pollen season. RESULTS: Sublingual immunotherapy with cedar pollen extract did not improve the clinical symptoms of the cedar pollinosis patients combined with cypress pollinosis in the cypress pollen season. The cypress pollen specific IgE antibodies were found to demonstrate significant seasonal changes. CONCLUSION: The presence of cypress pollinosis should therefore be taken into consideration when planning the optimal treatment for cedar pollinosis. Sublingual immunotherapy with cedar pollen extract may not be effective for cypress pollinosis.  相似文献   
10.
Y Horiguchi  T Nakai    K Kume 《Infection and immunity》1991,59(3):1112-1116
The effects of Bordetella bronchiseptica dermonecrotic toxin on the structure and function of a clonal osteoblastic cell line, MC3T3-E1, were investigated. The toxin induced a morphological change in the cells from a spindle shape to a spherical form with many blebs. The toxin-treated cells were viable and grew to form confluent cell layers composed of irregularly shaped cells and multinuclear cells. The toxin inhibited elevation of alkaline phosphatase activity in the cells in a dose-dependent manner at concentrations from 10 pg to 10 ng/ml. The accumulation of type I collagen in the cells was also reduced by the toxin. Since high alkaline phosphatase activity and accumulation of collagen are closely linked to differentiation of the cells into osteoblasts, it is considered likely that B. bronchiseptica dermonecrotic toxin impairs the ability of the cells to differentiate.  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-23

京公网安备 11010802026262号