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   1675篇
  免费   75篇
  国内免费   2篇
耳鼻咽喉   16篇
儿科学   76篇
妇产科学   58篇
基础医学   231篇
口腔科学   46篇
临床医学   94篇
内科学   347篇
皮肤病学   43篇
神经病学   66篇
特种医学   39篇
外科学   350篇
综合类   58篇
预防医学   58篇
眼科学   53篇
药学   150篇
中国医学   1篇
肿瘤学   66篇
  2023年   15篇
  2022年   16篇
  2021年   39篇
  2020年   17篇
  2019年   24篇
  2018年   42篇
  2017年   33篇
  2016年   25篇
  2015年   42篇
  2014年   74篇
  2013年   82篇
  2012年   125篇
  2011年   150篇
  2010年   64篇
  2009年   54篇
  2008年   76篇
  2007年   85篇
  2006年   73篇
  2005年   75篇
  2004年   68篇
  2003年   57篇
  2002年   54篇
  2001年   61篇
  2000年   54篇
  1999年   39篇
  1998年   18篇
  1997年   12篇
  1996年   11篇
  1995年   8篇
  1994年   4篇
  1993年   6篇
  1992年   22篇
  1991年   26篇
  1990年   28篇
  1989年   24篇
  1988年   19篇
  1987年   9篇
  1986年   11篇
  1985年   19篇
  1983年   8篇
  1980年   7篇
  1979年   13篇
  1978年   8篇
  1977年   4篇
  1976年   5篇
  1975年   4篇
  1974年   8篇
  1973年   4篇
  1971年   4篇
  1970年   4篇
排序方式: 共有1752条查询结果,搜索用时 15 毫秒
1.
The regulation by gastrointestinal polypeptide hormones of contraction and relaxation of functionally isolated smooth muscle cells from gastric antrum of the rabbit has been investigated. Gastrin, cholecystokinin (CCK-8) and motilin induced a rapid contraction of isolated cells: significant response occurred within a 5-sec incubation with these peptides and maximal response (40% decrease in cell length) after 30 sec. A higher sensitivity of smooth muscle cells to gastrin and CCK-8 than to motilin stimulations was demonstrated (EC50 = 10 pM for both gastrin and CCK-8 and EC50 = 1 nM for motilin). The minimal gastrin fragment required to get full contraction was the C-terminal pentapeptide amide common to gastrin and CCK. Proglumide inhibited gastrin- or CCK-8- but not motilin-induced contractions with an IC50 of 50 microM. contraction induced by gastrin and motilin required normal levels of extracellular calcium, whereas that due to CCK-8 seemed to be independent of extracellular calcium. Vasoactive intestinal polypeptide (VIP) caused a relaxation of smooth muscle cells maximally contracted by carbachol or CCK-8 or gastrin (EC50 = 2.2 nM) with a parallel increase in intracellular cAMP content.  相似文献   
2.
SETTING: A private infertility care and in vitro fertilisation (IVF) centre in Northern India. OBJECTIVES: To describe the prevalence, clinical spectrum, management strategy and outcome of infertility due to female genital tuberculosis (GTB) diagnosed with the help of a simplified tuberculosis (TB) algorithm. DESIGN: Data from 150 women with infertility (Group I) and 47 women with general gynaecological problems (Group II) were analysed. RESULTS: GTB was diagnosed in 7.2% of Group I and 2.8% of Group II women. Anti-tuberculosis treatment resulted in resolution of symptoms other than infertility in over 90% of cases. Of the total 20 pregnancies in the group, 10 were obtained in 32 IVF treatment patients. CONCLUSIONS: A definitive bacteriological diagnosis was generally difficult to achieve in GTB before administration of anti-tuberculosis treatment. A high index of suspicion and several other morphological and/or laboratory criteria were employed. It is suggested that a step-wise algorithm can help in the management of these cases.  相似文献   
3.
4.
A patient of chronic obstructive pulmonary disease (COPD) with cor-pulmonale and chronic respiratory failure, who was given intermittent positive pressure ventilation at home, is reported. The patient did remarkably well on home mechanical ventilatory support. We believe this to be the first case report of domiciliary mechanical ventilation in a patient of COPD from India.  相似文献   
5.
6.
7.
The complex electrical impedance of a goat eye lens is studied in the frequency range 10mHz−10Hz at room temperature, using a computer-controlled AC impedance system. AC impedance software (model 368, version 2.2) is employed to determine the total impedance and capacitance of the eye lens at various frequencies. A Cole-Cole plot of the eye lens material is drawn between the real component of impedance Z′ and the imaginary component Z″ for each excitation frequency that shows a perfect arc of a semicircle, with its centre lying below the abscissa at an angle of 35°. The half-angle ϕ between R0 and R is found to be 55°, which mathematically demonstrates the selective permeability of the eye lens. Using graphical analysis of the Cole-Cole plot, characteristic frequency fc and distribution factor α are observed to be 1Hz and 0.77, respectively. At characteristic frequency, capacitance and total impedance are found to be 1.14μF and 9.08kΩ. The effect of electrode polarisation on capacitance is corrected, based on Fricke's power function. The observed electrical parameters are then used to explain the multiple current path through various tissue compartments. Further, an attempt is made to explain the results on the basis of a possible dipolar model.  相似文献   
8.
Pancreatoblastoma or infantile pancreatic carcinoma is a rare pancreatic tumor with distinct acinar and squamoid cell differentiation that generally affects infants and young children. Ultrasound and CT scan may be useful but preoperative diagnosis is often quite difficult. The outcome is generally favourable. A such case of 10 years old boy with an abdominal mass is being presented.  相似文献   
9.
A computer assisted AC impedance system is used to measure the DC voltage—current (V-I) characteristics and AC impedance of a goat eye lens using a two-probe Ag−AgCl electrode system. The measurement of the V-I characteristics shows that when a DC voltage from 0mV to 30mV is applied, the resultant current decreases from an initial value of 0.58μA to 0.006μA. However, when the voltage is increases beyond 30mV, the current increases and reaches a value of 0.9μA at 100mV. The data on the frequency response (0.01–10 Hz) of the impedance of lens tissue show an inverse relationship with frequency. The effect of various DC voltages, namely 0, 30, 50, 100 and 200 mV, on the impedance of the eye lens is also investigated over a frequency range of 0.01–10 Hz. The measurement results for both V-I characteristics and AC impedance further suggest the presence of a 30 mV voltage compartment in the goat eye lens.  相似文献   
10.
Impedance plethysmographic observations have been correlated with aortographic observations in 57 patients suspected of aortic occlusive diseases. Aortic occlusions have been characterised by marked decrease in blood flow index and significant increase in differential pulse arrival time at thigh level bilaterally. Atherosclerotic affection of the aorta has been featured by a bilateral decrease in the value of blood flow index as well as differential pulse arrival time at thigh level. Leriche's syndrome, however, has been found to decrease the blood flow index moderately at thigh in both the legs without any significant change in differential pulse arrival time. Aortography in all the patients has confirmed the diagnosis made by impedance plethysmography.  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