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   2011篇
  免费   144篇
  国内免费   5篇
耳鼻咽喉   15篇
儿科学   84篇
妇产科学   227篇
基础医学   232篇
口腔科学   20篇
临床医学   242篇
内科学   332篇
皮肤病学   44篇
神经病学   213篇
特种医学   63篇
外国民族医学   1篇
外科学   275篇
综合类   19篇
一般理论   2篇
预防医学   112篇
眼科学   79篇
药学   107篇
中国医学   2篇
肿瘤学   91篇
  2022年   19篇
  2021年   26篇
  2020年   17篇
  2019年   32篇
  2018年   49篇
  2017年   27篇
  2016年   27篇
  2015年   31篇
  2014年   45篇
  2013年   61篇
  2012年   101篇
  2011年   88篇
  2010年   70篇
  2009年   37篇
  2008年   81篇
  2007年   67篇
  2006年   84篇
  2005年   84篇
  2004年   76篇
  2003年   62篇
  2002年   58篇
  2001年   54篇
  2000年   72篇
  1999年   56篇
  1998年   33篇
  1997年   25篇
  1996年   20篇
  1995年   15篇
  1994年   14篇
  1993年   30篇
  1992年   19篇
  1991年   51篇
  1990年   32篇
  1989年   55篇
  1988年   33篇
  1987年   45篇
  1986年   40篇
  1985年   45篇
  1984年   26篇
  1983年   17篇
  1982年   18篇
  1979年   37篇
  1978年   18篇
  1977年   18篇
  1975年   20篇
  1973年   20篇
  1971年   13篇
  1970年   14篇
  1969年   15篇
  1966年   14篇
排序方式: 共有2160条查询结果,搜索用时 15 毫秒
1.
2.
The influence of such individual characteristics as age, sex, morphological characteristics (CDD angle, length of femoral neck, total and medullary diameter and score on the Singh osteoporosis index) on the loading capacity and deformation of the proximal end of the femur were determined in this experimental study. In all, 341 femora taken from the cadavers of persons who had died at over 60 years of age were tested under alternating load in up to 4000 cycles and, if no instability occurred, also under static load. The loading capacity and deformation were compared. The loading capacity was significantly higher in male femora with (5441 +/- 257 N) than in female femora (4273 +/- 1850 N). The loading capacity also decreased with increasing age and with decreasing CCD angle and Singh index score (higher degree of osteoporosis). Because of the high standard deviation in each group these differences were not significant.  相似文献   
3.
In a single outbreak on the East coast of Madagascar, more than 500 people, 98 of whom died, were poisoned by the flesh of a shark, Carcharhinus amboinensis. From clinical symptoms it can be concluded that this poisoning is due to ciguatera toxins. It is the first case of a severe outbreak caused by a shark, and it is the first case with a mortality rate of 20%.  相似文献   
4.
In 61 breast cancer patients the effect of an combined adjuvant chemo-/immunotherapy with thymopentin (Timunox, Cilag) on different parameters of cell-mediated immunity (Leucocyte Migration Inhibition Test, serum level of tumor necrosis factor alpha, IL 2, Interferon alpha and distribution of lymphocyte subsets in the peripheral blood) and the clinical course of disease was evaluated and compared to patients receiving only chemotherapy. In cancer patients additionally treated with thymopentin an increase of the interferon alpha serum level could be observed, whereas the other parameters examined did not change. In the control group the percentage of T helper cells decreased under chemotherapy (p less than 0.05). Due to the short time of observation of 49 months until now no significant changes concerning the disease free interval and the time of survival between both groups could be found. Possibly the additional administration of thymopentin in breast cancer patients at least leads to a reduction of the immunosuppressive side effects of an adjuvant chemotherapy.  相似文献   
5.
Laserspectroscopy with near-infrared light is newly available for clinical application. The equipment consists of a near-infrared data collection unit (NIRDCU) and a personal computer. Emission of laser light at wavelengths of 775, 805, 845 and 904 nm is provided by the four laser diodes of the NIRDCU. By analyzing changes of optical density during laser radiation, information is obtained regarding the intracellular redox state and relative changes of blood volume. During measurement with the system on the fetal scalp during delivery we were able to get a first impression of the method's potential. While the application of the laser sensors is still cumbersome, signals providing information of the relative changes of hemoglobin concentration, relative changes of blood volume and cytochrome aa3 seems achievable. Laserspectrophotometric monitors may become safe, low cost and portable instruments for the non-invasive assessment of the biochemical and biophysical status in the fetus.  相似文献   
6.
Thirty-one combined transrectal ultrasonographic and urodynamic studies were performed in 24 patients with spinal cord lesions at different levels between C4 and T12. Ultrasonography provided accurate real-time imaging of the bladder neck, prostatic urethra and external sphincter during the bladder filling phase as well as during the voiding phase. Bladder and rectal pressures, sphincter EMG and uroflow were recorded simultaneously. Transrectal ultrasonography contributed significantly to the accuracy of diagnosing detrusor-sphincter dyssynergia. Sphincter contractions were clearly visualised with ultrasonographic video monitoring. This imaging method was especially helpful in sorting out the problems of 3 patients with poor emptying of bladder after endoscopic sphincterotomy. One had a urethral stricture and the other 2 had sphincters that opened adequately but bladders that emptied poorly because of detrusor hypocontractility. Other problems, such as benign prostatic hyperplasia and false passage, were also easily recognised. Transrectal ultrasonography not only provides accurate information but also involves no exposure to radiation and thus precludes the need for costly lead-shielded examination rooms.  相似文献   
7.
The comparative fatty acid analysis of extractable and non-extractable lipids of Escherichia coli W 1655 F+ and its stable protoplast type L-form shows quantitative as well as qualitative differences. From 10 different fatty acids obtained 16:0, 17:0, and 18:0 are present at about the same quantities in the lipid fractions of the bacterial and L-form. The absence of larger amounts of 12:0, 14:0, and 14:βOH fatty acids in non-extractable L-form lipids reflects the loss of the cell wall in L-form cells. 16:1 fatty acid was found in L-form lipids only. This qualitative difference and the 2–3 times higher content of 18:1 in L-form lipids and the 7 times lower content of cyc 19:0 in extractable lipids of the L-form may be interpreted as alterations characteristic for the changed composition of the cytoplasmic membrane in L-form cells.  相似文献   
8.
9.
Although it is known that men and women differ in their music preferences and emotional reactions to music, little is known about sex differences in physiological reactions to music. In our study, we therefore set out to examine the differential reactivity to two musical stimuli that elicit distinct psychological and physiological reaction patterns. Fifty-three healthy subjects (mean age: 26.13, SD: 3.97; 26 males, 27 females) were examined. Heart rate, electrodermal activity, skin temperature, salivary cortisol, salivary alpha-amylase, and psychological variables were assessed during the course of the whole study. Following baseline assessment, two musical stimuli, which were carefully selected and rated in a pre-study as relaxing and pleasant (renaissance music) and arousing and unpleasant (heavy metal), respectively, were introduced. They were presented on two different days in a randomized order. Whereas psychological variables did not differ between men and women, results of electrophysiological measures indicate significantly different reactivity patterns between men and women. Women displayed elevated response curves to the arousing and unpleasant stimulus, whereas men did not. However, no differences were found with regards to endocrine measures in saliva. Our results demonstrate sex differences in reactivity patterns to musical stimuli in psychophysiological measures. In our study, we were able to show that women tend to show hypersensitivity to aversive musical stimuli. This finding is in accordance with previous literature on sex differences in emotion research. Furthermore, our study indicates that the confounding effects of sex differences have to be considered when using musical stimuli for emotion induction.  相似文献   
10.
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