全文获取类型
收费全文 | 35722篇 |
免费 | 1609篇 |
国内免费 | 182篇 |
专业分类
耳鼻咽喉 | 354篇 |
儿科学 | 802篇 |
妇产科学 | 403篇 |
基础医学 | 4572篇 |
口腔科学 | 942篇 |
临床医学 | 2206篇 |
内科学 | 9787篇 |
皮肤病学 | 543篇 |
神经病学 | 2434篇 |
特种医学 | 1216篇 |
外科学 | 6265篇 |
综合类 | 164篇 |
一般理论 | 3篇 |
预防医学 | 1063篇 |
眼科学 | 379篇 |
药学 | 2562篇 |
中国医学 | 158篇 |
肿瘤学 | 3660篇 |
出版年
2023年 | 180篇 |
2022年 | 314篇 |
2021年 | 569篇 |
2020年 | 294篇 |
2019年 | 423篇 |
2018年 | 516篇 |
2017年 | 451篇 |
2016年 | 512篇 |
2015年 | 520篇 |
2014年 | 709篇 |
2013年 | 908篇 |
2012年 | 1471篇 |
2011年 | 1572篇 |
2010年 | 934篇 |
2009年 | 844篇 |
2008年 | 1576篇 |
2007年 | 1712篇 |
2006年 | 1726篇 |
2005年 | 1867篇 |
2004年 | 1787篇 |
2003年 | 1752篇 |
2002年 | 1747篇 |
2001年 | 1253篇 |
2000年 | 1341篇 |
1999年 | 1176篇 |
1998年 | 568篇 |
1997年 | 409篇 |
1996年 | 391篇 |
1995年 | 365篇 |
1994年 | 321篇 |
1993年 | 344篇 |
1992年 | 830篇 |
1991年 | 752篇 |
1990年 | 737篇 |
1989年 | 775篇 |
1988年 | 677篇 |
1987年 | 639篇 |
1986年 | 576篇 |
1985年 | 546篇 |
1984年 | 352篇 |
1983年 | 302篇 |
1982年 | 164篇 |
1979年 | 272篇 |
1978年 | 204篇 |
1977年 | 171篇 |
1974年 | 163篇 |
1973年 | 176篇 |
1972年 | 173篇 |
1971年 | 160篇 |
1970年 | 163篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cytosolic calcium concentration-force relation during contractions in the rabbit femoral artery: time-dependency and stimulus specificity. 下载免费PDF全文
1. By use of front-surface fluorometry with fura-2-loaded rabbit femoral arterial strips, both the cytosolic Ca2+ concentration ([Ca2+]i) and force were simultaneously monitored. By utilizing the [Ca2+]i-force curves, we were thus able to examine the temporal changes in the relationships between [Ca2+]i and force ([Ca2+]i-force relationship) during contractions induced by a high external K+ solution, noradrenaline (NA) and 5-hydroxytryptamine (5-HT). 2. The 'basic' [Ca2+]i-force relationship of the Ca(2+)-induced contractions was obtained by the cumulative applications of extracellular Ca2+ (0-10 mM) during 118 mM K(+)-depolarization (Ca(2+)-contractions). 3. When each vascular strip was exposed to high external K+ (30 mM K(+)-118 mM K+) solutions, the [Ca2+]i abruptly increased until it reached a peak, and then slightly decreased and eventually reached a steady-state level. The force also rapidly rose to reach a maximum plateau level. The changes in [Ca2+]i were more rapid than those in the force. Thus, the [Ca2+]i-force curves observed during the contractions induced by high+ (30 mM-118 mM) solutions showed a counter-clockwise rotation, over time. The entire curve shifted to the right, in a concentration-dependent manner, as compared with the line of the 'basic' [Ca2+]i-force relationship of the Ca(2+)-contraction. However, the [Ca2+]i-force relationship of the steady-state of contractions induced by the single dose applications of high K+ (30 mM-118 mM) overlapped with the line of the 'basic' [Ca2+]i-force relationship of Ca(2+)-contractions. 4. As references, the levels of [Ca2+]i and the force at rest (without stimulation) and at the steady-state of the contractions induced by a single dose application of 118 mM K+ solution were designated as 0% and 100%, respectively. When the vascular strips were exposed to NA (10(-5) M) and to 5-HT (10(-4) M), the [Ca2+]i abruptly rose, and reached a peak (107.1 +/- 5.8%) and 101.3 +/- 2.8%, respectively) after 1 min and 2 min, respectively (the [Ca2+]i-rising phase), and thereafter declined with a similar time course (the [Ca2+]i-declining phase) until reaching a low steady level (the steady-state phase). The force induced by 10(-5) M NA and 10(-4) M 5-HT reached a peak at 4 min (129%) and at 2 min (115%), respectively, and thereafter gradually declined. In contrast to the similarity in the [Ca2+]i transient between NA and 5-HT, the force induced by NA declined more slowly and reached higher steady levels than that seen with 5-HT.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
72.
73.
During the span of five years from October, 1987 to December, 1992, we have operated on six cases of carotid body tumours. Total excision was performed in five patients; one patient had 90% of the tumour excised. All patients had pre-operative balloon occlusion test; only one patient showed electroencephalographic changes. Three patients required intra-operative intraluminal shunts for various reasons. Microvascular Doppler flowmetery confirmed patency and correct placement of the shunt. Elective use of the intraluminal shunt is very useful for safe excision of carotid body tumours. Microneurosurgical techniques were used for all patients. There were no cerebrovascular sequelae and 25% of patients experienced cranial nerve injury. Average follow up was three years and none of the total excision patients have had recurrence of the tumours. 相似文献
74.
Development and evaluation of a presurgical preparation program 总被引:2,自引:1,他引:1
Three presurgical preparation programs were developed and evaluated in an Australian hospital utilizing an additive component design. The component basic to all three preparation programs was modeling. This technique was compared with the additional components of teaching child coping skills and parent coping skills via videotape. Subjects were 28 children between the ages of 4 and 13 years who were scheduled for elective surgery. Anxiety of both the children and parents was assessed by self-report and behavior observation. Results indicated that there was no further anxiety reduction by the addition of child and parent coping skills. Results are discussed in terms of the viability of teaching coping skills via videotape particularly to parents. Methodological difficulties associated with research in this area are examined. 相似文献
75.
Koichi Murata Yasuaki Nakagawa Takashi Suzuki Masahiko Kobayashi Seiya Kotani Takashi Nakamura 《Knee surgery, sports traumatology, arthroscopy》2007,15(10):1261-1263
Intraosseous ganglia of the glenoid are rare, and their etiology is unknown. This report describes a case of an intraosseous
ganglion about to cause fracture of the glenoid. The patient was a 61-year-old woman with a painful left shoulder with a limited
range of motion. Her symptoms did not improve after non-operative treatment. Arthroscopic examination showed a cartilage defect
and erosion in the posteroinferior portion of the glenoid, behind which computed tomography (CT) showed a cystic lesion of
the glenoid. There was no communication between the cyst and the joint space. The patient was treated by curettage and an
autogenous cancellous bone graft from the iliac crest. Two years after the operation, the patient was almost free from pain,
and CT showed good integration of the bone graft. 相似文献
76.
Aortic arch replacement with proximal first technique. 总被引:2,自引:0,他引:2
Yuji Miyamoto Kenji Onishi Masataka Mitsuno Koichi Toda Masao Yoshitatsu Kazuo Abe 《Annals of thoracic and cardiovascular surgery》2003,9(6):389-393
BACKGROUND: Deep hypothermic circulatory arrest (DHCA) without retrograde cerebral perfusion (RCP) has a strict time limit. We modified a surgical technique for anastomosis to shorten the period of DHCA and unilateral cerebral perfusion (UCP). METHODS: Between March 1993 and August 2001, retrospective analysis was done on 23 consecutive patients, who underwent aortic arch replacement with branches. The patients were divided into two groups: DHCA group and UCP group. The DHCA group, in which DHCA alone and without additional cerebral perfusion was performed, comprised of nine patients. Proximal aortic anastomosis was performed first during systemic cooling; then both the brachiocephalic artery and left carotid artery were reconstructed with the branches of the artificial graft during circulatory arrest; thereafter, cerebral and coronary perfusions were resumed. The UCP group, in which DHCA was not used but right hemisphere perfusion during deep hypothermia was performed when the origin of brachiocephalic artery was safely clamped, consisted of 14 patients. RESULTS: Mean time of DHCA was 18.8+/-4.2 minutes and that of right hemisphere perfusion time was 11.0+/-3.8 minutes, respectively. Twenty-one patients survived the surgery (91.3%), and two (8.7%) died during hospitalization. Transient cerebral complication occurred in four patients in the DHCA group and all recovered. Logistic regression analysis revealed that DHCA was the only parameter to significantly influence temporary neurological dysfunction. There was no other significant difference between the two groups. CONCLUSION: With our modified and simple surgical technique for aortic arch repair, we were able to successfully shorten the DHCA time and right hemisphere perfusion time. However, because DHCA was the only parameter to significantly influence temporary neurological dysfunction, some form of continuous cerebral perfusion at deep hypothermia may be a safer method to preserve cerebral function. 相似文献
77.
Erika Saitoh Yuki Yokomizo Chih-Hung Chang Sonya Eremenco Hiyori Kaneko Kunihiko Kobayashi 《Nippon Ika Daigaku zasshi》2007,74(6):402-408
BACKGROUND: The Functional Assessment of Cancer Therapy-Lung (FACT-L) questionnaire, which consists of a core questionnaire (the General Measure of FACT [FACT-G]) and a 9-item Additional Concerns comprised of a 7-item Lung Cancer Subscale (LCS), was developed in an English-speaking culture. The validation of the Japanese FACT-G was reported previously, and this report describes the cross-cultural validation of the LCS. METHODS: The Japanese version of the LCS was developed through an iterative forward-backward translation sequence used throughout the FACT Multilingual Translation Project. In evaluating psychometric performance, its construct validity was investigated with Cronbach's alpha coefficient and factor analysis. Clinical validities of a known-groups comparison and longitudinal validity were also investigated. RESULTS: The FACT-L was administered twice to 180 patients with lung cancer within 2 weeks. The Japanese LCS had borderline values for Cronbachs alpha coefficients (0.62-0.67). Factor analysis indicated that the LCS had the three dimensions of respiratory symptoms, appetite plus body weight, and clear thinking. For clinical validity, a known-groups comparison showed that the LCS could differentiate patients according to truth disclosure, as Japanese doctors sometimes do not fully inform terminally ill patients. However, responsiveness was not proved when performance status was used as an anchor, probably owing to the short interval between the administration of the two measures. CONCLUSION: The Japanese version of the LCS asked questions about multiple symptoms of patients with lung cancer, as did the original English LCS. The longitudinal clinical validity of the Japanese version should be investigated in future clinical trials. 相似文献
78.
79.
Repeated injections of 45 ng/kg of maitotoxin into the peritoneal cavities of male ICR mice resulted in marked atrophy of lymphoid tissues, a reduction of lymphocytes in the circulating blood, reduced immunoglobulin M in serum, and an increase of calcium content in the adrenal glands. A single injection of 200 ng/kg of maitotoxin induced a marked increase in total calcium content of the adrenal glands as well as in plasma cortisol concentration (about seven times control) within 1 hr. In contrast, mice pretreated with CoCl2, a calcium channel inhibitor, and/or adrenalectomized mice, showed no discernible changes in the lymphoid tissues after repeated injections of maitotoxin. It is thus suggested that maitotoxin first stimulates calcium influx in the adrenal glands, which then causes the release of cortisol into the blood. The excess amount of cortisol in serum produces acute involution of the thymus and other lymphoid tissues. 相似文献
80.
K Nakamura T Kituta Y Nakamura Y Nakajima K Kobayashi T Uchida 《Cancer Detection and Prevention》1987,10(1-2):37-55
A newly established cancer marker, the PFK inhibition test, has been further examined for its capacity to detect malignant neoplasms irrespective of the organs in which cancer cells start proliferating. We tested 1,160 sera from cancer patients and compared them with 756 normal sera, using histograms and normal paper for analysis of accumulated frequency. PFK activity through the influence of normal sera showed normal distribution, and cancerous sera shifted to the inhibitory site with an irregular shape. From these analyses, the patients were classified into the following types: normal range: PFK greater than SD (standard deviation of PFK activity in normal sera); suspicious range: SD greater than PFK greater than 2SD, must be given the PFK test again; and dangerous range: PFK less than 2SD, further examination must be carried out to detect cancer. Fifty percent of the sera from all the cancer patients inhibited PFK beyond 2 SD of normal sera. We also analyzed organ-associated PFK distribution, eg, gastric, colorectal, and mammary cancer. In gastric cancer, PFK inhibition was stronger in accordance with how far a particular stage of cancer had progressed. However, 50% of sera from stage I gastric cancer patients was positive beyond the cut-off line of 2 SD. We examined 104 sera from patients diagnosed as benign prostatic hypertrophy and found malignant cells in 10 patients whose sera tended to be positive in PFK inhibition. The PFK inhibitory factor in the body fluids of cancer patients was fractionated by Sephadex G-75 gel filtration and DEAE ion exchange chromatography. The approximate molecular weight of this factor was 13,000 daltons. The factor was resistant to heat and acid (0.1 N HCl and H2SO4) and was sensitive to 0.1 N NaOH and phosphate buffer. Diluted sulfuric acid and ammonium sulfate made an inactive NaOH-treated sample active when lyophilized following dialysis against distilled water. PFK inhibition by cancerous sera was eliminated by fructose-2,6-bisphosphate (the strongest activator of PFK) in a dose-dependent manner. PFK attached to agarose beads was found to be reversible even after being inhibited by cancerous body fluids and ATP water solution. Although PFK is apt to decay in a low pH range, the established procedure did not destroy PFK, but induced a direct inhibition of PFK by ATP through the ATP inhibition site on the PFK molecule. The PFK inhibitor may possibly function as a proton carrier and release protons to activate the ATP inhibition site.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献